Abstract
Background:
The current study was intended to analyze the genotype distribution of the tumor suppressor genes TP53 and TP21, and to investigate their potential association with acute radiotherapy –induced toxicities, such as skin reactions and mucositis, in normal tissues of head and neck cancer (HNC) patients receiving radiotherapy.
Materials & Methods:
Two hundred and fifty HNC patients undergoing radiotherapy were enrolled in this study and the acute toxicity reactions and radiotherapy response were recorded. The potential association of two single nucleotide polymorphisms (SNPs) (rs1042522, rs28934571) of TP53 gene and (rs1801270, rs1059234) SNPs of TP21 gene, with the risk of acute skin toxicity reactions was analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing methods.
Results:
The findings revealed that the homozygous recessive (C/C) genotype of the 72G>C polymorphism in the TP53 gene exhibited a significantly increased association with acute skin toxicity in (HNC) patients undergoing radiotherapy (OR = 4.32, 95% CI: 1.87–10.01; p = 0.0006, and the heterozygous (G/C) genotype of the same polymorphism demonstrated a robust correlation with acute skin reactions (OR = 9.23, 95% CI: 4.40–19.23; p < 0.0001). The heterozygous variant (G/C) genotype of TP53 was identified as a significant risk factor for oral mucositis exceeding grade 2 severity in HNC patients receiving radiotherapy, with an odds ratio of 4.15 (95% CI: 2.21–7.76; p < 0.0001).
Conclusion:
The results of genetic polymorphisms of TP53 and TP21 genes and their association with radiotherapy induced acute toxicities demonstrated significant association of TP53, G72C polymorphism of rs1042522 SNP with both acute radiotherapy induced dermatitis and mucositis.
Key Words: Head and neck cancer, Radiotherapy, TP53, TP21, Genetic polymorphism, acute toxicity
Introduction
Head and Neck cancer (HNC) is the most prevalent cancer in many countries of the world, accounting for approximately 900, 000 cases and over 450, 000 deaths annually [1]. The incidence of HNC has increased significantly worldwide in past few decades and represents a leading cause of cancer-related deaths among both men as well as women in Asian countries like China, Pakistan, Thailand and India [2]. In the Indian subcontinent, HNC has emerged as a major public health burden, representing approximately 30% of all cancers and contributing to 245,811 new cases and 130,139 deaths in 2022 [3-4]. Established risk factors for HNC include the use of tobacco in various forms, excessive alcohol consumption, poor oral hygiene, and exposure to environmental carcinogens [5-6]. Along with, , genetic susceptibility plays a critical role in HNC pathogenesis, involving complex, multistage processes mediated by alterations in DNA repair genes, tumor suppressor genes, oxidative stress-related genes, and epigenetic modifications [7-9]. Radiotherapy (RT) remains a cornerstone of HNC treatment, either as monotherapy or in combination with chemotherapy; however, radiation-induced toxicities in surrounding normal tissues significantly impact patients’ quality of life [10-11]. The most common acute radio-toxicities occurred in the HNC patients are oral mucositis, dermatitis and dysphagia, while late toxicities include fibrosis, osteoradionecrosis or xerostomia [12-13]. Emerging evidence highlights the pivotal role of genetic factors in determining individual clinical radiosensitivity and susceptibility to radiation-induced adverse effects [14-15].
Several studies have investigated the role of genetic polymorphisms in tumor suppressor genes in predicting radiosensitivity and the development of normal tissue toxicity following radiotherapy. Polymorphisms such as Arg72Pro and Arg249Ser in the TP53 gene have been extensively associated with an increased risk of various cancers; however, their specific contribution to radiotherapy-induced normal tissue reactions has not been thoroughly elucidated. Nevertheless, emerging evidence suggests that the TP53 Pro72Arg polymorphism, in conjunction with the p21 Ser31Ser genotype, may significantly influence the susceptibility to acute radiotherapy-induced toxicities in cancer patients [16-18]. Previous studies have also demonstrated that Arg72Pro SNP (rs1042522) in the TP53 gene influences radiosensitivity in different cancer patients and contributes to develop adverse effects following radiotherapy in patients with prostate [19], breast [20] gastric [21], lung [22] and head and neck cancers [23-25]. However, the relationship between radiotherapy induced toxicities and genetic polymorphisms in tumor suppressor genes remains controversial which showed no independent effect of TP53 polymorphisms with the risk of normal tissue toxicity following radiotherapy in breast [26-27] and prostate cancer patients [28-29]. Nevertheless, the combined genotypic effects of TP53 and TP21 polymorphisms have been implicated in increased susceptibility to acute radiotherapy induced toxicities in breast cancer patients. In contrast, no significant association of p21 polymorphisms and radiation-induced toxicity was observed in patients with non-small cell lung carcinoma [30]. Although numerous studies have investigated the role of genetic polymorphisms in radiation-responsive genes, there remains significant scope to further elucidate the association between specific gene variants and radiotherapy-induced normal tissue toxicity, particularly in HNC patients. Therefore, in the present study, we examined the potential association between two single nucleotide polymorphisms (SNPs) of the TP53 gene Pro72Arg (G>C; rs1042522) and Arg249Ser (G>T; rs28934571) and two SNPs of the TP21 gene C98A (rs1801270) and C70T (rs1059234) with the risk of developing acute skin toxicity following therapeutic radiotherapy in HNC patients.
Materials and Methods
Patient enrollment and Clinical Information
A total of 250 patients, histopathologically confirmed with HNC and visiting to Medical Oncology Out Patient Department (OPD) for the treatment at the Krishna Institute of Medical Sciences were enrolled in accordance based on predefined inclusion and exclusion criteria. Eligible participants included individuals aged between 25 to 85 years diagnosed with HNC on histopathology and no evidence of metastatic disease at the time of enrollment.
Treatment of HNC patients with radiotherapy & chemo-radiotherapy
All HNC patients were treated using three-dimensional conformal radiation therapy (3DCRT) or Intensity modulated radiation therapy (IMRT), based on computed tomography (CT)-guided planning, simulation, verification, and rigorous quality assurance protocols. Patients were treated using Linear accelerator (Model: Unique Performance, Make: Varian Medical System, USA) 6-Mega Volt (MV) (X-ray) with the total radiotherapy dose ranging from 60- 66 Gy (2 Gy per fractions for 5 days a week) with volumetric modulated arc therapy (VMAT) technique. Patients after surgical resection having positive margins were given a dose of 66 Gy in 33 fractions. Concurrent chemotherapy was added where clinically indicated, using cisplatin at a dose of 40 mg/m2 , administered weekly for up to 6 cycles in combination with radiotherapy.
Follow up and Toxicity Assessment
To assess acute normal tissue toxicity, patients were prospectively followed for three months post-radiotherapy to evaluate clinical outcomes, including partial, complete, or no response, disease stability or progression, early mortality, and treatment-related toxicity. The facial and cervical skin regions were designated as target areas for monitoring acute radiation-induced skin reactions. Acute adverse effects, specifically oral mucositis and skin reactions, were documented weekly during radiotherapy at 1 and 3 months post-treatment, according to the Radiation Therapy Oncology Group (RTOG) criteria. Acute radiation toxicity was defined as any injury manifesting from the initiation of radiotherapy up to three months post-treatment. Severity grading of radiation-induced dermatitis and oral mucositis was performed by radiation oncologists using the RTOG scale. Patients presenting with grade >2 skin reactions or mucositis were classified as radiosensitive and compared against patients with grade ≤2 toxicity to investigate associations with polymorphisms in tumor suppressor genes. All patient information was systematically recorded, and participants were monitored for a minimum of three months following therapy. Written informed consent was obtained from all participants prior to enrollment. The study protocol was reviewed and approved by the Institutional Ethics Committee of Krishna Institute of Medical Sciences.
Blood sample collection and genomic DNA isolation
Five milliliter (mL) of whole blood from patients was collected in sterile EDTA containing vacutainer after receiving informed consent. The blood sample from patients was collected before initiation of radiotherapy treatment. The genomic DNA extraction was carried out by salting out method where the whole blood was processed with lysis buffer-1 containing 10mM Tris-HCl pH-7.6, 320mM sucrose, 5mM MgCl2, 1% triton X-100, pH 7.6 to lyse RBCs, thereafter the sample was treated with the lysis buffer 2 to lyse out WBCs (10mM Tris- HCl, 11.4mM sodium citrate, 1mM EDTA, 1% SDS, pH-8.0). The sample was further treated with Proteinase K (200µg/µl) to digest the proteins and subsequently RNase A (200µg/µl). The genomic DNA was precipitated by addition of twice the volume of ice cold ethanol and 1/10th volume of 3M Sodium acetate (pH-5.2). The precipitated DNA was aggregated together by centrifugation. The obtained pellet of DNA was then resuspended in T10E1 buffer and was checked on 1% agarose gel for its quality and quantity. This purified DNA was used for further genotyping assays after quantitative and qualitative analysis.
Genotyping assays of Tumor suppressor (TP53 & TP21) genes
The genotyping assay of tumor suppressor genes (p53, p21), was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using appropriate primer set as shown in Table 1. The PCR conditions for amplification of TP53 (309 bp) codon -72, exon-4, Pro72Arg, G>C) and codon249 of exon-7 with Arg249Ser (G>T) polymorphisms and TP21 with codon 31 of exon-2, C98A (272bp) and TP21 at exon 3 (C70T) polymorphisms with 300 bp are depicted in Table 1. After performing PCR programme for each of the reaction, the PCR products were analyzed by agarose gel electrophoresis in Tris-Acetate-EDTA (TAE) buffer. The agarose gels stained with ethidium bromide (10 mg/mL) and visualized under UV Transilluminator and photographed in gel documentation system (BioRad Laboratories).
Table 1.
The List of Candidate Tumor Suppressor Genes (TP53 and TP21) Genes with Details of PCR and RFLP Procedures Including Primers and Restriction Enzymes
| Gene Genotype |
rs number |
Amino acid/ nucleotide change |
Primer Sequence Forward/Reverse |
PCR Conditions | PCR product size | Enzyme / Digestion conditions | Dominant (Wild type) | Hetero-zygous | Recessive (Mutant) |
|---|---|---|---|---|---|---|---|---|---|
|
TP53
Codon-72 Exon-4 Pro72Arg |
rs1042522 | (G>C) | FP: 5’-TTC ACC CAT CTA CAG TCC -3’ RP: 5’- CTC AGG GCA ACT GAC CGT-3’ |
950C- 5 min, 30 cycles of 950C- 30 sec, 520C-30 sec, 720C-30 sec, 720C- 10 min | 309 bp | 1 U of BstuI (Bsh12361) 370C Incubation for 16 hrs | 175bp, 134bp |
309bp, 175bp, 134bp |
309bp |
|
TP53
Codon-249 Exon-7 Arg249Ser |
rs28934571 | (G>T) | FP: 5’-GGC GAC AGA GCG AGATTC CA -3’ RP: 5’-GGG TCA GCG GCA AGCAGA GG -3’ |
950C- 5 min, 30 cycles of 950C- 20 sec, 600C-20 sec, 720C-20 sec, 720C- 10 min | 286 bp | 1 U of HaeIII (BsuRI) 370C Incubation for 16 hrs | 92bp, 66bp, Small fragments |
158bp, 92bp, 66bp, Small fragments | |
|
TP21
codon-31 exon-2 C98A |
rs1801270 | (C>A) | FP: 5’-GTC AGA ACC GGC TGG GGA TG-3’ RP: 5’-CTC CTC CCA ACT CAT CCC GG-3’ |
950C- 5 min, 30 cycles of 950C- 30 sec, 580C- 30 sec, 720C-30 sec, 720C- 10 min | 272 bp | 1 U of BpuI (BlpI) 370C Incubation for 16 hrs |
183 bp, 89 bp |
272 bp, 183 bp, 89 bp |
272bp |
|
TP21
exon-3 C70T |
rs1059234 | (C>T) | FP: 5’-CCC AGG GAA GGG TGT CCT-3’ RP: 5’-GGG CGG CCA GGG TAT GTA-3’ |
950C- 5 min, 30 cycles of 950C- 20 sec, 580C- 20 sec, 720C-20 sec, 720C- 10 min | 300 bp | 1 U of PstI 370C Incubation for 16 hrs |
126bp, 174bp |
300 bp, 174 bp, 126 bp |
300 bp |
SNP, Single nucleotide polymorphism; OR, Odds ratio; CI, Confidence interval; Significance p< 0.05; *, Indicates significant Odds Ratio (p<0.05); p value determined based on χ2
Restriction Fragment Length Polymorphism
After confirmation of DNA amplification, each PCR product was digested with an appropriate restriction enzyme for genotyping. Ten micro liters of the PCR products digested at 37°C overnight with specific restriction enzymes in 20 µL reaction mixtures containing buffer supplied with each restriction enzyme (Table 1). After the overnight incubation, digestion products were separated on a 2-3% low EEO agarose (GeNei) gel at 100 V for 30 min stained with ethidium bromide and photographed with Gel Documentation System.
Statistical Analysis
The genotypic frequencies for tumor suppressor genes in the patient’s were determined. The relative risk and odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated using unconditional multiple logistic regression analysis to assess the association between acute toxicity grades and SNPs. Statistical significance was defined as a p-value less than 0.05. Acute post-radiotherapy adverse events were categorized based on the severity of skin reactions and oral mucositis, with events classified as grade >2 considered clinically significant. The patients with oral mucositis grade >2 are radiosensitive groups (cases) compared with ≤2 grade (controls) for determining their association with polymorphism of different tumor suppressor genes. All statistical analyses were performed using SPSS version 11.0 software.
Results
Demographic and Clinical characteristics of study population
A total of 250 patients, aged 25 to 85 years (median age: 55 years), were enrolled in the study. Of these, 187 were male (74.80%) and 63 were female (25.20%). The majority of patients were tobacco smokers (87.60%) compared to non-smokers (12.40%). When stratified by the primary site of cancer, the distribution was as follows: oropharynx (36.0%), hypopharynx (22.0%), oral cavity (23.60%), nasopharynx (2.80%), larynx (8.0%), and other sites (4.80%). Of the total cohort, 26% underwent radiotherapy alone, while 74% received a combination of radiation therapy and chemotherapy. Regarding tumor size, 65.60% of patients presented with tumors larger than 2 cm, while 34.40% had tumors ≤ 2 cm. Among the 250 patients treated with radiotherapy, 63 (25.20%) exhibited grade >2 (grade 3) severe skin reactions, including intense erythema, moderate edema, patchy moist desquamation, increased pain, yellow exudate secretion, itching, and skin tightening. The remaining 187 (74.80%) patients reported grade ≤2 skin reactions, such as faint erythema, itching, and skin tightening. Additionally, 132 (52.80%) patients exhibited grade >2 (grade 3 or 4) oral mucositis, characterized by severe pain, fibrinous mucositis, ulceration, hemorrhage, and necrosis. In contrast, 118 (47.20%) patients experienced grade ≤2 mucositis, with symptoms including irritation, patchy mucositis, serosanguineous discharge, and moderate pain in response to radiation exposure.
Genotype Distribution of TP53 and TP21 genes and radiotherapy toxicity in HNC patients
The tumor suppressor TP53 and TP21 were analyzed to assess the association of polymorphisms with genes radiotherapy-induced normal tissue toxicity. Univariate logistic regression analysis of the polymorphisms in TP53 and TP21 revealed a significant association between the TP53 G72C polymorphism (rs1042522 SNP) and both acute skin reactions and mucositis (Table 2). The analysis indicated that the homozygous recessive (C/C) genotype of the TP53 72G>C polymorphism was associated with a 4.32-fold increased risk of acute skin reactions (OR=4.32, 95% CI: 1.87–10.01; p=0.0006), while the heterozygous (G/C) genotype was linked to a 9.23-fold increased risk (OR=9.23, 95% CI: 4.40–19.23; p<0.0001) in HNC patients following radiotherapy. Additionally, the univariate analysis indicated that the odds ratio for severe oral mucositis (grade >2) in patients with the recessive allele of the TP53 gene was 3.54 times higher (95% CI: 1.74–7.14, p=0.0005) (Table 2). The heterozygous (G/C) genotype of TP53 also showed a 4.15-fold increased risk of severe oral mucositis (OR=4.15, 95% CI: 2.21–7.76; p<0.0001) in HNC patients exposed to radiotherapy. However, no significant association was observed between the rs28934571 SNP of TP53 and the rs1801270 and rs1059234 SNPs of TP21 with normal tissue toxicity, specifically regarding skin reactions or mucositis, as recessive and heterozygous genotypes did not show significantly higher frequencies in affected patients.
Table 2.
Univariate Analysis of Polymorphisms of Tumor Suppressor TP53, and TP21 Genes and Radiation Induced Skin Reactions and Mucositis in Head and Neck Cancer Patients
| Gene Name | Genotype | Skin reaction ≤2 n=187 |
Skin reaction >2 n=63 |
OR 95% CI |
p value | Oral mucositis ≤2 n=118 |
Oral mucositis >2 n=132 |
OR 95% CI |
p value |
|---|---|---|---|---|---|---|---|---|---|
| TP53 G72C (rs1042522) |
G/G 35 C/C G/C +C/C |
120 35 32 67 |
13 35 15 50 |
1 (Reference) 9.23 (4.40-19.33) 4.32 (1.87-10.01) 6.88 (3.49-13.59) |
<0.0001* 0.0006* <0.0001* |
83 20 15 35 |
50 50 32 82 |
1(Reference) 4.15 (2.21-7.76) 3.54 (1.74-7.14) 3.88 (2.29-6.60) |
<0.0001* 0.0005* <0.0001* |
| TP53 G249T (rs28934571) |
G/G G/T T/T G/T +T/T |
114 43 30 73 |
43 7 13 20 |
1 (Reference) 0.43 (0.18-1.03) 1.14 (0.54-2.40) 0.72 (0.39-1.33) |
0.059 0.713 0.301 |
74 27 17 44 |
83 23 26 49 |
1(Reference) 0.75 (0.40-1.43) 0.83 (0.39-1.77) 0.99 (0.59-1.65) |
0.398 0.647 0.978 |
| TP21 C98A (rs1801270) |
C/C C/A A/A C/A +A/A |
146 40 1 41 |
50 12 1 13 |
1 (Reference) 0.87 (0.42-1.80) 2.92 (0.17-47.55) 0.92 (0.45-1.86) |
0.718 0.451 0.829 |
94 24 1 25 |
102 28 1 29 |
1(Reference) 1.07 (0.58-1.98) 0.92 (0.05-14.94) 1.06 (0.58-1.95) |
0.816 0.954 0.828 |
| TP21 C70T (rs1059234) |
C/C C/T T/T C/T +T/T |
134 47 6 53 |
48 11 4 15 |
1 (Reference) 0.65 (0.31-1.36) 1.86 (0.50-6.87) 0.79 (0.40-1.53) |
0.256 0.351 0.485 |
88 25 5 30 |
94 33 5 38 |
1 (Reference) 1.23 (0.68-2.24) 0.93 (0.26-3.34) 1.18 (0.67-2.07) |
0.486 0.919 0.55 |
Association of TP53 and TP21 gene polymorphisms with risk of toxicity effects of radiotherapy in HNC patients
The logistic regression analysis in the current study revealed no significant association between the 249G>T polymorphism of TP53 and the 98C>A and 70C>T polymorphisms of TP21 with skin reactions in HNC patients following radiotherapy (Table 3). The multivariate analysis produced odds ratios (ORs) with 95% confidence intervals (CIs) for patients experiencing acute dermatitis with the recessive allele of TP53 (rs28934571), which showed an OR of 1.10 (95% CI: 0.54–2.23; p=0.783), and for the heterozygous G/T genotype, which showed an OR of 0.51 (95% CI: 0.21–1.20; p=0.126). Both associations were non-significant with respect to acute skin reactions in HNC patients. The ORs for the heterozygous variant alleles of TP21 rs1801270 (OR=1.96, 95% CI: 0.17–22.05; p=0.585) and rs1059234 (OR=1.51, 95% CI: 0.45–5.04; p=0.497) also indicated no significant association with skin toxicity following radiotherapy in HNC patients. However, the odds ratio for patients with grade >2 oral mucositis showed a significant increase associated with the recessive (C/C) genotype of TP53 (rs1042522) with an OR of 3.26 (95% CI: 1.44–7.36; p=0.004) and the heterozygous (G/C) genotype with an OR of 5.11 (95% CI: 2.54–10.29; p<0.0001). The multivariate logistic regression analysis also evaluated the association of tumor suppressor genes, particularly radiosensitive genes, with oral mucositis in HNC patients treated with radiotherapy. The OR for patients experiencing grade >2 oral mucositis with the recessive (C/C) genotype of TP53 (rs1042522) was 1.81 (95% CI: 1.04–3.15; p=0.035), and for the heterozygous (G/C) genotype, it was 1.90 (95% CI: 1.16–3.09; p=0.009), both indicating significant associations with oral mucositis toxicity following radiotherapy in HNC patients (Table 4). Therefore, no significant association was observed between genetic variants of TP53 (rs28934571) and TP21 (rs1801270, rs1059234) and the development of increased acute skin toxicity or oral mucositis reactions after radiotherapy.
Table 3.
Association of Polymorphisms ofTumor Suppressor TP53 and TP21 Genes with Risk of Skin Reaction after Radiotherapy in Head and Neck Cancer Patients
| Gene /SNP | Genotypes | All Patients | Radiosensitive patients | OR 95% CI | p value |
|---|---|---|---|---|---|
|
TP53
(rs1042522) |
G/G | 133 | 13 | 1 (Reference) | |
| G/C | 70 | 35 | 5.11 (2.54-10.29) | <0.0001* | |
| C/C | 47 | 15 | 3.26 (1.44-7.36) | 0.004* | |
| G/C +C/C | 117 | 50 | 4.37 (2.26-8.44) | <0.0001* | |
|
TP53
(rs28934571) |
G/G | 157 | 43 | 1 (Reference) | |
| G/T | 50 | 7 | 0.51 (0.21-1.20) | 0.126 | |
| T/T | 43 | 13 | 1.10 (0.54-2.23) | 0.783 | |
| G/T +T/T | 93 | 20 | 0.78 (0.43-1.41) | 0.421 | |
|
TP21
(rs1801270) |
C/C | 196 | 50 | 1 (Reference) | |
| C/A | 52 | 12 | 0.90 (0.44-1.82) | 0.779 | |
| A/A | 2 | 1 | 1.96 (0.17-22.05) | 0.585 | |
| C/A +A/A | 54 | 13 | 0.84 (0.47-1.86) | 0.867 | |
|
TP21
(rs1059234) |
C/C | 182 | 48 | 1 (Reference) | |
| C/T | 58 | 11 | 0.71 (0.35-1.47) | 0.368 | |
| T/T | 10 | 4 | 1.51 (0.45-5.04) | 0.497 | |
| C/T +T/T | 68 | 15 | 0.83 (0.43-1.59) | 0.586 |
SNP, Single nucleotide polymorphism; OR, Odds ratio; CI, Confidence interval; Significance p< 0.05; *, Indicates significant Odds Ratio (p<0.05); p value determined based on χ2.
Table 4.
Association of Polymorphisms of Tumor Suppressor TP53 and P21 Genes with Risk of Mucositis after Radiotherapy in Head and Neck Cancer Patients
| Gene /SNP | Genotypes | All Patients | Radiosensitive patients | OR 95% CI | p value |
|---|---|---|---|---|---|
|
TP53
(rs1042522) |
G/G | 133 | 50 | 1 (Reference) | |
| G/C | 70 | 50 | 1.90 (1.16-3.09) | 0.009* | |
| C/C | 47 | 32 | 1.81 (1.04-3.15) | 0.035* | |
| G/C+ C/C | 117 | 82 | 1.86 (1.21-2.86) | 0.004* | |
|
TP53
(rs28934571) |
G/G | 157 | 83 | 1 (Reference) | |
| G/T | 50 | 23 | 0.87 (0.49-1.52) | 0.626 | |
| T/T | 43 | 26 | 1.14 (0.65-1.99) | 0.635 | |
| G/T +T/T | 93 | 49 | 0.99 (0.64-1.54) | 0.987 | |
|
TP21
(rs1801270) |
C/C | 196 | 102 | 1 (Reference) | |
| C/A | 52 | 28 | 1.03 (00.61-1.73) | 0.897 | |
| A/A | 2 | 1 | 0.96 (0.08-10.72) | 0.974 | |
| C/A+ A/A | 54 | 29 | 1.03 (0.61-1.71) | 0.903 | |
|
TP21
(rs1059234) |
C/C | 182 | 94 | 1 (Reference) | |
| C/T | 58 | 33 | 1.10 (0.67-1.80) | 0.701 | |
| T/T | 10 | 5 | 0.96 (0.32-2.91) | 0.954 | |
| C/T+ T/T | 68 | 38 | 1.08 (0.67-1.72) | 0.741 |
SNP, Single nucleotide polymorphism; OR, Odds ratio; CI, Confidence interval; Significance p< 0.05; *, Indicates significant Odds Ratio (p<0.05); p value determined based on χ2.
Association of TP53 and TP21 gene polymorphisms with tumor and node response towards radiotherapy in HNC patients
Univariate logistic regression analysis was performed to evaluate the association between TP53 (rs1042522, rs28934571) and TP21 (rs1801270, rs1059234) gene polymorphisms with clinically and histopathologically confirmed tumor grades and tumor response to radiotherapy, as presented in Tables 5 and 6. The univariate analysis revealed that the rs1042522 SNP of the TP53 gene was not associated with histological tumor grades >III, and the rs28934571 SNP showed no association with either clinical or histopathological tumor grades. However, the recessive (C/C) genotype of TP53 (rs1042522) was significantly associated with high tumor stage (stage >3), with an odds ratio (OR) of 2.22 (95% CI: 1.12–4.38; p=0.02). Similarly, the heterozygous C/A genotype of TP53 (rs1801270) was associated with histological tumor grade >3 (OR=2.16, 95% CI: 1.10–4.25; p=0.024), while the rs1059234 SNP of TP21 did not show any significant association with clinical stage >3 or histopathological grade >III (Table 5). Regarding the relationship between TP53 and TP21 polymorphisms and tumor response to radiotherapy, no association was found between the rs1042522 and rs28934571 SNPs of TP53 and tumor or nodal response to radiotherapy, as shown in Table 6. Furthermore, the C98A polymorphism of TP21 (rs1801270) showed that neither the recessive nor the heterozygous genotypes were associated with tumor or nodal response in HNC patients following radiotherapy, evaluated three months post-treatment. A significant positive association was observed for the heterozygous (C/T) genotype of the TP21 (rs1059234) SNP with complete tumor response to radiotherapy (OR=2.19, 95% CI: 1.06–4.51; p=0.033), whereas the recessive T/T genotype was not associated with tumor or nodal response. Additionally, the C70T polymorphism of TP21, with the recessive T/T genotype (OR=3.47, 95% CI: 0.83–14.50; p=0.088) and the heterozygous C/T genotype (OR=1.68, 95% CI: 0.73–3.84; p=0.213), was not associated with nodal response in HNC patients to radiotherapy. When HNC patients were stratified based on body mass index (BMI), no significant association was found between any TP53 or TP21 gene polymorphisms and the risk of acute radiotherapy toxicity (Table 7).
Table 5.
Association between Genotypes of Tumor Suppressor TP53 and TP21 Genes with Tumor Stage and Tumor Grade in Head and Neck Cancer Patients
| Gene Name (SNP) |
Genotype | Tumor stage | OR 95% CI | p value | Histological Grade | OR 95% CI |
p value | ||
|---|---|---|---|---|---|---|---|---|---|
| T1, T2 n=134 |
T3, T4 n=116 |
I, II n=103 |
III, IV n=147 |
||||||
| TP53 G72C (rs1042522) |
G/G G/C C/C G/C+ C/C |
80 35 19 54 |
53 35 28 63 |
1 (Reference) 1.50 (0.84-2.70) 2.22 (1.12-4.38) 0.76 (1.06-2.91) |
0.166 0.020* 0.027* |
58 30 15 45 |
75 40 32 72 |
1(Reference) 1.03 (0.57-1.84) 1.64 (0.817-3.33) 1.23 (0.74-2.05) |
0.918 0.409 |
| TP53 G249T (rs28934571) |
G/G G/T T/T G/T+ T/T |
85 28 21 49 |
72 22 22 44 |
1 (Reference) 0.92 (0.48-1.76) 1.23 (0.62-2.42) 1.06 (0.63-1.77) |
0.818 0.537 0.823 |
66 20 17 37 |
91 30 26 56 |
1(Reference) 1.08(0.56-2.08) 1.10 (0.55-2.20) 1.09 (0.65-1.85) |
0.799 0.767 0.726 |
| TP21 C98A (rs1801270) |
C/C C/A A/A C/A+ A/A |
106 28 0 28 |
90 24 2 26 |
1 (Reference) 1.00 (0.54-1.86) 5.88 (0.27-124.15) 1.09 (0.59-1.99) |
0.975 0.254 0.771 |
87 14 2 16 |
109 38 0 38 |
1(Reference) 2.16 (1.10-4.25) 0.15 (0.007-3.37) 1.89 (0.99-3.62) |
0.024* 0.238 0.053 |
| TP21 C70T (rs1059234) |
C/C C/T T/T C/T+ T/T |
95 33 6 39 |
87 25 4 29 |
1 (Reference) 0.82 (0.45-1.50) 0.72 (0.19-2.66) 0.81 (0.46-1.42) |
0.532 0.631 0.467 |
73 24 6 30 |
109 34 4 38 |
1 (Reference) 0.94 (0.52-1.73) 0.44 (0.12-1.63) 0.84 (0.48-1.48) |
0.863 0.223 0.566 |
SNP, Single nucleotide polymorphism; CR, Complete Response; PR, Partial Response; NR, No Response; RR, Risk ratio; CI, Confidence interval; Significance p< 0.05; *, Indicates significant Odds Ratio (p<0.05), p value determined based on χ2
Table 6.
Association between Genotypes of Tumor Suppressor TP53 and TP21 Genes with Tumor and Node Response in Head and Neck Cancer Patients towards Radiotherapy
| Gene Name (SNP) |
Genotype | Tumor Response | Risk Ratio (RR) 95% CI |
p value | Node Response | Risk Ratio (RR) 95% CI |
p value | ||
|---|---|---|---|---|---|---|---|---|---|
| CR | PR/NR | CR | PR/NR | ||||||
| n=209 | n=41 | n=217 | n=33 | ||||||
|
TP53
G72C (rs1042522) |
G/G | 108 | 25 | 1 (Reference) | 113 | 20 | 1(Reference) | ||
| G/C | 61 | 9 | 0.63 (0.27-1.45) | 0.284 | 61 | 9 | 0.83 (0.35-1.94) | 0.673 | |
| C/C | 40 | 7 | 0.75 (0.30-1.88) | 0.548 | 43 | 4 | 0.52 (0.16-1.62) | 0.264 | |
| G/C+ C/C | 101 | 16 | 0.68 (0.34-1.35) | 0.276 | 104 | 13 | 0.70 (0.33-1.49) | 0.361 | |
|
TP53
G249T (rs28934571) |
G/G | 130 | 27 | 1 (Reference) | 134 | 23 | 1(Reference) | ||
| G/T | 41 | 9 | 1.05 (0.45-2.42) | 0.896 | 43 | 7 | 0.94 (0.38-2.36) | 0.909 | |
| T/T | 38 | 5 | 0.59 (0.18-1.94) | 0.394 | 40 | 3 | 0.43 (0.12-1.53) | 0.195 | |
| G/T+ T/T | 79 | 14 | 0.80 (0.32-2.02) | 0.647 | 83 | 10 | 0.70 (0.31-1.54) | 0.38 | |
|
TP21
C98A (rs1801270) |
C/C | 166 | 30 | 1 (Reference) | 174 | 22 | 1(Reference) | ||
| C/A | 41 | 11 | 1.48 (0.68-3.20) | 0.315 | 42 | 10 | 1.88 (0.82-4.27) | 0.13 | |
| A/A | 2 | 0 | 1.09 (0.05-23.30) | 0.955 | 1 | 1 | 7.90 (0.47-130.99) | 0.148 | |
| C/A+ A/A | 43 | 11 | 1.41 (0.65-3.05) | 0.375 | 43 | 11 | 2.02 (0.91-4.48) | 0.083 | |
|
TP21
C70T (rs1059234) |
C/C | 157 | 25 | 1 (Reference) | 162 | 20 | 1 (Reference) | ||
| C/T | 43 | 15 | 2.19 (1.06-4.51) | 0.033* | 48 | 10 | 1.68 (0.732-3.84) | 0.213 | |
| T/T | 9 | 1 | 0.69 (0.08-5.74) | 0.738 | 7 | 3 | 3.47 (0.83-14.50) | 0.088 | |
| C/T+ T/T | 52 | 16 | 1.93 (0.95-3.89) | 0.065 | 55 | 13 | 1.91 (0.89-4.10) | 0.094 | |
RS, Radiosensitive; SNP, Single nucleotide polymorphism; CR, Complete Response; PR, Partial Response; NR, No Response; RR, Risk ratio; CI, Confidence interval; Significance p< 0.05; *, Indicates significant Odds Ratio (p<0.05); p value determined based on χ2
Table 7.
Association of Tumor Suppressor TP53 and TP21 Gene Polymorphisms with Risk of Acute Toxicity Effects of Radiotherapy in Head and Neck Cancer Patients Stratified by BMI
| Gene Name (SNP) |
Genotype | Normal Weight | Overweight | ||||||
|---|---|---|---|---|---|---|---|---|---|
| (BMI ≤20) | (BMI ≤20) | ||||||||
| All Patients | RS patients | OR 95% CI | p value | All Patients | RS patients | OR 95% CI | p value | ||
|
TP53
G72C (rs1042522) |
G/G | 55 | 22 | 1 (Reference) | 78 | 36 | 1 (Reference) | ||
| G/C | 33 | 10 | 0.75 (0.31-1.79) | 0.528 | 47 | 17 | 0.78 (0.39-1.54) | 0.482 | |
| C/C | 23 | 16 | 0.71 (0.33-1.50) | 0.375 | 33 | 14 | 0.91 (0.43-1.92) | 0.823 | |
| G/C+ C/C | 56 | 26 | 1.16 (0.58-2.28) | 0.667 | 80 | 31 | 0.83 (0.47-1.48) | 0.549 | |
|
TP53
G249T (rs28934571) |
G/G | 76 | 32 | 1 (Reference) | 81 | 36 | 1 (Reference) | ||
| G/T | 17 | 9 | 1.25 (0.50-3.11) | 0.62 | 33 | 13 | 0.88 (0.41-1.88) | 0.753 | |
| T/T | 18 | 9 | 1.18 (0.48-2.92) | 0.708 | 25 | 18 | 1.62 (0.78-3.33) | 0.19 | |
| G/T+ T/T | 35 | 18 | 1.22 (0.60-2.46) | 0.576 | 58 | 31 | 1.20 (0.66-2.16) | 0.537 | |
|
TP21
C98A (rs1801270) |
C/C | 83 | 36 | 1 (Reference) | 113 | 54 | 1 (Reference) | ||
| C/A | 27 | 12 | 1.02 (0.46-2.24) | 0.951 | 25 | 22 | 1.84 (0.95-3.55) | 0.069 | |
| A/A | 1 | 0 | 0.76 (0.03-19.16) | 0.869 | 1 | 1 | 2.09 (0.12-34.09) | 0.604 | |
| C/A+ A/A | 28 | 12 | 0.98 (0.45-2.15) | 0.976 | 26 | 23 | 1.85 (0.96-3.53) | 0.062 | |
|
TP21
C70T (rs1059234) |
C/C | 80 | 43 | 1 (Reference) | 102 | 48 | 1 (Reference) | ||
| C/T | 28 | 18 | 1.19 (0.59-2.40) | 0.615 | 30 | 15 | 1.06 (0.52-2.15) | 0.866 | |
| T/T | 3 | 2 | 1.24 (0.19-7.71) | 0.817 | 7 | 3 | 0.91 (0.22-3.67) | 0.895 | |
| C/T+ T/T | 31 | 20 | 1.20 (0.61-2.35) | 0.595 | 37 | 18 | 1.03 (0.53-1.99) | 0.921 | |
Discussion
Radiotherapy is a crucial treatment modality for HNC, typically administered in fractions to enhance treatment efficacy. However, radiotherapy can induce toxic reactions in normal tissues. Prominent toxicities resulting from radiotherapy in HNC patients include subcutaneous fibrosis, oral mucositis, and skin reactions such as dermatitis, particularly following adjuvant radiation therapy or concurrent chemoradiotherapy. Host genetic factors play a significant role in determining an individual’s susceptibility to radiation-induced adverse effects, and a better understanding of these factors could help mitigate the long-term consequences of radiotherapy. Single nucleotide polymorphisms (SNPs) in genes involved in the DNA repair pathway may influence the ability of adjacent cells to repair radiation-induced DNA damage, potentially leading to more severe toxicity. Additionally, polymorphisms in tumor suppressor genes may offer insights into their role in the radiation response during treatment. Although extensive research has been conducted on the genetic variants of tumor suppressor genes and their involvement in cancer development, limited literature exists regarding their association with radiotherapy outcomes. Therefore, identifying genetic variations in these genes is essential for personalizing therapy, improving treatment safety and outcomes, and addressing the potential reduction in radiotherapy efficacy in patients. Tumor suppressor proteins, such as p53 and p21, are key regulators of cellular responses and play essential roles in controlling cell growth and apoptosis in response to radiation-induced damage. Upon exposure to ionizing radiation, p53 is rapidly activated and facilitates G1 phase cell cycle arrest by transactivating the expression of p21, thereby inducing cell cycle checkpoint control [31]. Polymorphisms in the TP53 and TP21 genes have been associated with increased susceptibility to both acute and chronic radiation-induced toxicities across various cancers, although findings have been inconsistent. In this study, we aimed to investigate the polymorphisms of the tumor suppressor genes TP53 and TP21 and their potential association with radiotherapy-induced acute toxicities in HNC patients. Our results demonstrated that the Arg72Pro polymorphism of p53 was significantly associated with an increased risk of acute radiation-induced toxicities, including dermatitis (OR=4.32, 95% CI: 1.87–10.01; p=0.0006) and mucositis (OR=3.54, 95% CI: 1.74–7.14; p=0.0005) following radiotherapy. These findings are consistent with previous studies that have linked p53 polymorphisms to adverse toxicity outcomes in HNC [32] and breast cancer [17] patients undergoing radiotherapy, either alone or in combination with chemoradiotherapy. Several studies have also reported an association between the p53 Arg72Pro polymorphism and the risk of skin toxicities in patients undergoing radiotherapy for breast [26], lung [22], and prostate cancer [29]. In the present study, no significant correlation was found between the p21 Ser31Arg polymorphism and the risk of acute toxicities, such as dermatitis or mucositis, which is consistent with other studies on p21 polymorphisms in breast cancer [17, 33]. When examining the clinicopathological features and tumor and nodal response of head and neck cancer (HNC) patients to radiotherapy, as well as their association with p53 and p21 gene polymorphisms, our results confirmed that the recessive (C/C) genotype of TP53 (rs1042522) was associated with a higher tumor stage (p=0.02). Similarly, the heterozygous (C/T) genotype of TP21 (rs1059234) was significantly associated with a complete tumor response to radiotherapy (p=0.033).
Conclusion: The results obtained from this study evidenced a significant association between Arg72Pro polymorphism of the TP53 gene with risk of acute radiation-induced toxicities, such as dermatitis and mucositis in HNC patients treated with radiotherapy. Specifically, the results suggest a significant correlation between TP53 G72C polymorphism (rs1042522 SNP) with both acute dermatitis and mucositis. Further investigation of genetic variants and their association with radiotherapy response and its adverse toxicity effects is required to be out to confirm our findings by using large number of samples and broad range of SNPs for comprehensive genotyping.
Author Contribution Statement
Concept: AKG, RAG, SJB, Design: AKG, KDD, RAG, Experimental Studies: AKG, RAG, KDD Clinical studies: AKG, RAG Data analysis: KDD, AKG, Statistical analysis: AKG, KDD Manuscript preparation: AKG, RAG, KDD, All authors read and approved the final manuscript.
Acknowledgments
Acknowledgements
Funding statement
Authors are thankful to Indian Council of Medical Research (ICMR) for financial assistance to the research project (Grant No. NCD/Ad-hoc/120/2021-22 dated 22/11/2021.
Approval
The study protocol was approved by protocol committee of Krishna Vishwa Vidyapeeth (Deemed to be University)
Ethics Committee Approval
The study protocol was approved by Institutional Ethics Committee of Krishna Vishwa Vidyapeeth (Deemed to be University), Karad.
Declaration of Conflict of interest
The authors declare that they have no competing financial or any other conflict of interests that could have appeared to influence the work reported in this paper.
Abbreviations
HNC: Head and neck cancer
TP53: Tumor suppressor 53
TP21 Tumor suppressor 21
SNP: Single nucleotide polymorphism
PCR-RFLP: Polymerase Chain Reaction-Restriction Fragment Length Polymorphism
DNA: Deoxyribose Nucleic Acid
OR: Odds ratio
CI: Confidence interval
RT: Radiotherapy
OPD:Out Patient Department
MV: Mega Volt
VMAT: volumetric modulated arc therapy
RTOG: Radiation Therapy Oncology Group
mL: milliliter
µl: Microliter
EDTA: Ethylenediamdie Tetra acetate
SDS: Sodium dodecyl Sulphate
TAE: Tris-Acetate-EDTA
References
- 1.Global Cancer Observatory. World Health Organization; International Agency for Research on Cancer. Available from: https://gco. [Google Scholar]
- 2.Chaturvedi AK, Anderson WF, Lortet-Tieulent J, Curado MP, Ferlay J, Franceschi S, et al. Worldwide trends in incidence rates for oral cavity and oropharyngeal cancers. J Clin Oncol. 2013;31(36):4550–9. doi: 10.1200/JCO.2013.50.3870. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Sathishkumar K, Chaturvedi M, Das P, Stephen S, Mathur P. Cancer incidence estimates for 2022 & projection for 2025: Result from National Cancer Registry Programme, India. Ind J Med Res. 2022;156(4&5):598–607. doi: 10.4103/ijmr.ijmr_1821_22. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Bagal S, Budukh A, Thakur JS, Dora T, Qayyumi B, Khanna D, et al. Head and neck cancer burden in India: an analysis from published data of 37 population-based cancer registries. Ecancer med sci. 2023;17:1603. doi: 10.3332/ecancer.2023.1603. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Marcu LG, Yeoh E. A review of risk factors and genetic alterations in head and neck carcinogenesis and implications for current and future approaches to treatment. J Cancer Res Clin Oncol. 2009;135(10):1303–14. doi: 10.1007/s00432-009-0648-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Hari Ram, Sarkar J, Kumar H, Konwar R, Bhatt ML, Mohammad S. Oral cancer: Risk factors and molecular pathogenesis. J Maxillofacial Oral Surg. 2011;10(2):132–7. doi: 10.1007/s12663-011-0195-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Fostira F, Koutsodontis G, Vagia E, Economopoulou P, Kotsantis I, Sasaki C, et al. JCO Precision Oncol. Predisposing germline mutations in young patients with squamous cell cancer of the oral cavity;2:1–8. doi: 10.1200/PO.18.00022. [DOI] [PubMed] [Google Scholar]
- 8.Vukovic V, Stojanovic J, Vecchioni A, Pastorino R, Boccia S. Systematic Review and Meta-analysis of SNPs from Genome-Wide Association Studies of Head and Neck Cancer. Otolaryngol- Head Neck Surg. 2018;159(4):615–24. doi: 10.1177/0194599818792262. [DOI] [PubMed] [Google Scholar]
- 9.Campbell BR, Chen Z, Faden DL, Agrawal N, Li RJ, Hanna GJ, et al. The mutational landscape of early- and typical-onset oral tongue squamous cell carcinoma. Cancer. 2021;127(4):544–53. doi: 10.1002/cncr.33309. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Rodel C, Grabenbauer GG, Kuhn R, Papadopoulos T, Dunst J, Meyer M, et al. Combined-modality treatment and selective organ preservation in invasive bladder cancer: long-term results. J Clin Oncol. 2002;20(14):3061–71. doi: 10.1200/JCO.2002.11.027. [DOI] [PubMed] [Google Scholar]
- 11.Suk R, Gurubhagavatula S, Park S, Zhou W, Su L, Lynch TJ, et al. Polymorphisms in ERCC1 and grade 3 or 4 toxicity in non-small cell lung cancer patients. Clin Cancer Res. 2005;11(4):1534–8. doi: 10.1158/1078-0432.CCR-04-1953. [DOI] [PubMed] [Google Scholar]
- 12.Trotti A, Bellm LA, Epstein JB, Frame D, Fuchs HJ, Gwede CK, et al. Mucositis incidence, severity and associated outcomes in patients with head and neck cancer receiving radiotherapy with or without chemotherapy: A systematic siterature seview. Radiother Oncol. 2003;66(3):253–62. doi: 10.1016/s0167-8140(02)00404-8. [DOI] [PubMed] [Google Scholar]
- 13.Machtay M, Moughan J, Trotti A, Garden AS, Weber RS, Cooper JS, et al. Factors Associated With Severe Late Toxicity After Concurrent Chemoradiation for Locally Advanced Head and Neck Cancer: An RTOG Analysis. J Clin Oncol. 2008;26(21):3582–9. doi: 10.1200/JCO.2007.14.8841. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Andreassen CN, Dikomey E, Parliament M, West CM. Will SNPs be useful predictors of normal tissue radiosensitivity in the future? Radiother Oncol. 2012;105(3):283–8. doi: 10.1016/j.radonc.2012.11.003. [DOI] [PubMed] [Google Scholar]
- 15.Barnett GC, Coles CE, Elliott RM, Baynes C, Luccarini C, Conroy D, et al. Independent validation of genes and polymorphisms reported to be associated with radiation toxicity: a prospective analysis study. Lancet Oncol. 2012;13(1):65–77. doi: 10.1016/S1470-2045(11)70302-3. [DOI] [PubMed] [Google Scholar]
- 16.Vannini I, Zoli W, Tesei A, Rosetti M, Sansone P, Storci G, et al. Role of p53 codon 72 arginine allele in cell survival in vitro and in the clinical outcome of patients with advanced breast cancer. Tumor Biol. 2008;29(3):145–51. doi: 10.1159/000143400. [DOI] [PubMed] [Google Scholar]
- 17.Chang-Claude J, Ambrosone CB, Lilla C, Kropp S, Helmbold I, von Fournier D, et al. Genetic polymorphisms in DNA repair and damage response genes and late normal tissue complications of radiotherapy for breast cancer. Br J Cancer. 2009;100(10):1680–6. doi: 10.1038/sj.bjc.6605036. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Su M, Yin ZH, Wu W, Li XL, Zhou BS. Meta-analysis of associations between ATM Asp1853Asn and TP53 Arg72Pro polymorphisms and adverse effects of cancer radiotherapy. Asian Pac J Cancer Res. 2014;15(24):10675–81. doi: 10.7314/apjcp.2014.15.24.10675. [DOI] [PubMed] [Google Scholar]
- 19.Cesaretti JA, Stock RG, Lehrer S, Atencio DA, Bernstein JL, Stone NN, et al. ATM sequence variants are predictive of adverse radiotherapy response among patients treated for prostate cancer. Int J Radiat Oncol Biol Phy. 2005;61(1):196–202. doi: 10.1016/j.ijrobp.2004.09.031. [DOI] [PubMed] [Google Scholar]
- 20.Andreassen CN, Overgaard J, Alsner J, Overgaard M, Herskind C, Cesaretti JA, et al. ATM sequence variants and risk of radiation-induced subcutaneous fibrosis after postmastectomy radiotherapy. Int J Radiat Oncol Biol Phys. 2006;64(3):776–83. doi: 10.1016/j.ijrobp.2005.09.014. [DOI] [PubMed] [Google Scholar]
- 21.Kim JG, Sohn SK, Chae YS. TP53 codon 72 polymorphism associated with prognosis in patients with advanced gastric cancer treated with paclitaxel and cisplatin. Cancer Chemo Pharmacol. 2009;64(2):355–60. doi: 10.1007/s00280-008-0879-3. [DOI] [PubMed] [Google Scholar]
- 22.Yang M, Zhang L, Bi N, Ji W, Tan W, Zhao L, et al. Association of P53 and ATM polymorphisms with risk of radiation-induced pneumonitis in lung cancer patients treated with radiotherapy. Int J Radiat Oncol Biol Phys. 2011;79(5):1402–7. doi: 10.1016/j.ijrobp.2009.12.042. [DOI] [PubMed] [Google Scholar]
- 23.Tu HF, Chen HW, Kao SY, Lin SC, Liu CJ, Chang KW. MDM2 SNP 309 and p53 codon 72 polymorphisms are associated with the outcome of oral carcinoma patients receiving postoperative irradiation. Radiother Oncol. 2008;87(2):243–52. doi: 10.1016/j.radonc.2008.03.018. [DOI] [PubMed] [Google Scholar]
- 24.Xie X, Wang H, Jin H, Ouyang S, Zhou J, Hu J, et al. Expression of pAkt affects p53 codon 72 polymorphism-based prediction of response to radiotherapy in nasopharyngeal carcinoma. Radiat Oncol. 2013;8:117. doi: 10.1186/1748-717X-8-117. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Borchiellini D, Etienne-Grimaldi MC, Bensadoun RJ, Benezery K, Dassonville O, Poissonnet G, et al. Oral Oncol. Candidate apoptotic and DNA repair gene approach confirms involvement of ERCC1, ERCC5, TP53 and MDM2 in radiation-induced toxicity in head and neck cancer;67:70–6 . doi: 10.1016/j.oraloncology.2017.02.003. [DOI] [PubMed] [Google Scholar]
- 26.Tan XL, Popanda O, Ambrosone CB, Kropp S, Helmbold I, von Fournier D, et al. Association between TP53 and p21 genetic polymorphisms and acute side effects of radiotherapy in breast cancer patients. Br Cancer Res Treat. 2006;97(3):255–62. doi: 10.1007/s10549-005-9119-2. [DOI] [PubMed] [Google Scholar]
- 27.Badie C, Dziwura S, Raffy C, Tsigani T, Alsbeih G, Moody J, et al. Aberrant CDKN1A transcriptional response associates with abnormal sensitivity to radiation treatment. Brazilian J Cancer. 2008;98(11):1845–51. doi: 10.1038/sj.bjc.6604381. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Popanda O, Marquardt JU, Chang-Claude J, Schmezer P. Genetic variation in normal tissue toxicity induced by ionizing radiation. Mutation Res. 2009;667(1-2):58–69. doi: 10.1016/j.mrfmmm.2008.10.014. [DOI] [PubMed] [Google Scholar]
- 29.Cintra HS, Pinezi JC, Machado GD, de Carvalho GM, Carvalho AT, dos Santos TE, et al. Investigation of genetic polymorphisms related to the outcome of radiotherapy for prostate cancer patients. Disease Mark. 2013;35(6):701–10. doi: 10.1155/2013/762685. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Matsuzoe D, Hideshima T, Kimura A, Inada K, Watanabe K, Akita Y, et al. p53 mutations predict nonsmall cell lung carcinoma response to radiotherapy. Cancer Lett. 1999;135(2):189–94. doi: 10.1016/s0304-3835(98)00292-4. [DOI] [PubMed] [Google Scholar]
- 31.Mazzatti DJ, Lee YJ, Helt CE, O’Reilly MA, Keng PC. p53 modulates radiation sensitivity independent of p21 transcriptional activation. Am J Clin Oncol. 2005;28(1):43–50. doi: 10.1097/01.coc.0000139484.51715.5a. [DOI] [PubMed] [Google Scholar]
- 32.Sullivan A, Syed N, Gasco M, Bergamaschi D, Trigiante G, Attard M, et al. Polymorphism in wild-type p53 modulates response to chemotherapy in vitro and in vivo. Oncogene. 2004;23(19):3328–37. doi: 10.1038/sj.onc.1207428. [DOI] [PubMed] [Google Scholar]
- 33.Azzato EM, Driver KE, Lesueur F, Shah M, Greenberg D, Easton DF, et al. Effects of common germline genetic variation in cell cycle control genes on breast cancer survival: results from a population-based cohort. Br Cancer Res. 2008;10(3) doi: 10.1186/bcr2100. [DOI] [PMC free article] [PubMed] [Google Scholar]