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. 2014 Apr;43(4):453–459.

The TP53 Codon 72 Polymorphism and Risk of Sporadic Prostate Cancer among Iranian Patients

Farhad BABAEI 1, Seyed Ali AHMADI 2, Ramin ABIRI 3, Farhad REZAEI 1, Maryam NASERI 1, Mahmoud MAHMOUDI 4, Rakhshande NATEGH 1, Talat MOKHTARI AZAD 1,*
PMCID: PMC4433726  PMID: 26005655

Abstract

Background

The TP53 gene is one of the most frequently mutated genes amongst human malignancies, particularly TP53 codon 72 polymorphism. Furthermore, an association between the TP53 codon 72 variants and prostate cancer has been reported in several studies. Although some studies have indicated an association between the TP53 Arg/Arg variant and an increased risk for prostate cancer, other studies have shown a positive correlation between the TP53 Pro/Pro genotype instead. Therefore, to clarify if this polymorphism is associated with an increased risk of prostate cancer in Iranian men, we conducted a case-control study of 40 sporadic prostate cancer patients and 80 benign prostate hyperplasia cases.

Methods

The TP53 codon 72 was genotyped using an allele specific PCR.

Results

A significant association between the TP53 codon 72 genotype and prostate cancer risk was found (OR = 6.8, 95% CI = [1.8-25.1], P = 0.005). However, the results of this study did not support an association between age, the Gleason score nor TP53 genotype at codon 72 in prostate cancer patients.

Conclusions

TP53 codon 72 polymorphism may have a great impact in the development of prostate cancer.

Keywords: Sporadic prostate cancer, Benign prostate hyperplasia, TP53 codon 72 polymorphism

Introduction

Prostate cancer is the second most frequent cancer in men worldwide, with an estimated 903, 500 new cases and 258,400 deaths in 2008 (1, 2). Also, it is the second most common cancer with an estimated age-standardized incidence rate of 11.6 in Iranian men (3). While the natural history of prostate cancer is not recognized very well, several causes point to genetic defects, infection and inflammation (4–9). The TP53 gene, located on chromosome 17p13, is a tumor suppressor gene (10). The p53 is considered as ‘guardian of the genome’ because it plays a crucial role in the cell cycle arrest and inducing of apoptosis (11, 12). This gene is one of the most frequently mutated genes in human malignancies (13, 14). In particular, some studies have been supported a role for TP53 codon 72 polymorphism in development of various cancers (13, 15–17). This mutation is a G-to-C substitution at nucleotide position 313 that results in a change of arginine (CGC) to proline (CCC) (18). An in-vitro study has been shown that the TP53 Arg/Arg variant stimulates apoptosis and prevents transformation properly than the Pro /Pro genotype, indicating individuals with Pro/Pro genotype may be more susceptible for development of cancer (19). Patients with the Pro/Pro variant likely have a poor prognosis and survival, particularly cancers of the ovarian (20), breast (21), thyroid (22), esophageal squamous cell carcinoma (23) and hepatocellular carcinoma (17) or early age onset of cancer such as squamous cell carcinoma of the head and neck (24). An association between TP53 codon 72 variants and prostate cancer have been reported in several studies (15, 25, 26). Although some studies have been indicated an association between the TP53 Arg/Arg variant and an increased risk for prostate cancer (25, 27, 28), others have been shown a correlation between the TP53 Pro/Pro genotype instead (15, 26).

In the only study in North of Iran, no associations have been found between TP53 codon 72 variant and prostate cancer (25, 29).

To clarify if this polymorphism is associated with an increased risk of prostate cancer in Iranian men, we conducted a case-control study of 40 sporadic prostate cancer (PCa) and 80 benign prostatic hyperplasia (BPH) cases.

Materials and Methods

Study population and samples

A series of 120 formalin-fixed paraffin-embedded tissue samples including 40 PCa blocks and 80 BPH tissues were retrieved from the archives of the Pathology Laboratory of Sina Hospital in Tehran during 2011. All samples were taken with appropriate local ethical committee approval and informed consent was obtained from recruited patients.

None of the patients had received any chemotherapy or radiotherapy before the surgery. All cases were re-examined by pathologist to verify a Gleason score higher than 6.

TP53 codon 72polymorphism analysis

For each tissue sample, 10-μm sections were cut. Median sections were applied for molecular analysis. First and final sections were stained by hema-toxylin—eosin and were re-examined by the pathologist to verify a Gleason score higher than 6. To avoid potential contamination between specimens, the first four sections from each tissue sample were discarded, the microtome was cleaned with 70% ethanol and blades were changed before cutting the next block. Also, an empty block was cut between samples and applied as a PCR control to check potential cross-contamination through microtome use.

Genomic DNA was isolated according to previous published protocols with some modifications (30, 31). In brief, two 10 µm slices of each sample was de-paraffinized with xylen and digested with lysis buffer (50 mM Tris—HCl pH 8.5, 1 mM EDTA, 0.5 % Tween 20) and Proteinase K (200 µg per ml) at 37 °C, overnight. In the next step, DNA purification was performed by phenol— chloroform extraction and ethanol precipitation.

The TP53 codon 72 polymorphism analysis was carried out by using an allele specific PCR amplification. For each sample, PCR was done in two separate reactions by specific primers. In the first reaction that was specific to detect proline allele, p53Pro Plus primer (5’-GCCAGAGGCTGCTCCCCC-3’) with p53Minus primer was applied. In the second reaction that was specific for arginine allele, p53 Plus primer with p53Arg Minus (5’-CTGGTGCAGGGG-CCACGC-3’) primers was used (32). Amplification reaction was carried out in a 50-µl reaction mixture including 1.5 mM MgCl2, 50 µΜ of each dNTP, 20 pmol of each primer, 2 U of Taq DNA polymerase and 100-200 ng of DNA target. PCR performed as follows: an initial 1-min denaturation at 94 °C, followed by 32 cycles of 94 °C for 30 s, 59 °C for 30 s, 72 °C for 45 s and a final elongation at 72 °C for 5 min.

Statistical analysis

The observed and expected TP53 codon 72 allele frequencies for PCa and BPH groups were investigated by the Hardy—Weinberg equilibrium theory. The associations between diseases and variants were evaluated by calculating the Odds Ratio (OR) with 95% Confidence interval (CI). All statistical analysis was conducted using the EPI Info version 7. A two-sided P-value was considered statistically significant when it was < 0.05.

Results

This study investigated the TP53 codon 72 polymorphism on 40 PCa patients and 80 BPH individuals. The mean age (± SD) for patients with PCa and BPH were 69.85 (± 8.58) and 69.91 (± 8.05), respectively.

The TP53 codon 72 allele frequencies were studied using an allele specific PCR to detect arginine or proline (Fig. 1). Table 1 shows the frequencies of TP53 codon 72 variants in PCa and BPH groups. The frequencies of Arg/Arg, Arg/Pro and Pro/Pro alleles among PCa were 15 (37.5%), 15 (37.5%) and 10 (25%), respectively. In the BPH group, the frequencies of TP53 codon 72 genotypes were 41 (51.3%), 35 (43.7%) and 4 (5%), respectively. The TP53 codon 72 allele frequencies were in the Hardy-Weinberg equilibrium among PCa and BPH groups (X2 = 1.02, and X2= 2.27, df = 1; P > 0.05).

Fig. 1.

Fig. 1

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Allele specific PCR /Left to right: Proline/Proline hemozygous-Arginine/Proline heterozygous-Proline/Proline homozygous-Arginin/Arginine homozygous- negative control-Positive Control-1KbSize marker

Table 1.

Frequency of TP53 codon 72 variants in prostate cancer (PCa) and benign prostatic hyperplasia (BPH) cases

Genotype PCa (n=40) n (%) BPH (n=80) n (%) OR (95% CI) P-value
Arg/Arg 15 (37.5) 41 (51.3) 1
Arg/Pro 15 (37.5) 35 (43.7) 1.2 (0.5-2.7) 0.88
Pro/Pro 10 (25) 4 (5) 6.8 (1.8-25.1) 0.005
Pro/Arg + Pro/Pro 25 (62.5) 39 (48.7) 1.7 (0.8-3.8) 0.21
Arg allele 45 (56.3) 117 (73.1) 1
Pro allele 35 (43.7) 43 (26.9) 2.1 (1.2-3.7) 0.012
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As shown in table 1, the TP53 Pro/Pro genotype was more frequent in PCa cases in comparison to BPH subjects and this difference was statistically significant (OR = 6.8, 95% CI = [1.8-25.1], P = 0.005).

When stratifying the PCa and BPH groups by the age ≤ 65 versus > 65, an important association was found between the Pro/Pro variant and an increased risk of prostate cancer in patients older than 65 years old. In the age group > 65, individuals who carried Pro/Pro genotype showed a 9.9-fold higher risk (95% CI= 1.8-54.5, P = 0.009) of progression of prostate cancer in comparison to subjects who carried Arg/Arg. However, compared to BPH subjects (Table 2), no statistically significant association was observed between TP53 alleles and the risk of prostate cancer in PCa patients under the age of 66. Also, as stratifying the PCa group by the age of onset, no important correlation was found between the age of onset and risk of prostate cancer development. Although the Pro allele was more prevalent in age group ≤ 65 years old, this difference was not statistically significant (P=0.47).

Table 2.

Distribution of TP53 codon 72 variants in prostate cancer (PCa) and benign prostatic hyperplasia (BPH) cases stratified by age

Age (yr)
≤ 65 > 65
Genotype PCa(n=12) n (%) BPH (n=19) n (%) OR (95% CI) PCa (n=28) n (%) BPH (n=61) n (%) OR (95% CI)
Arg/Arg 3 (25) 8 (42.1) 1 12 (42.9) 34 (55.7) 1
Arg/Pro 6 (50) 9 (47.4) 2.7 (05-13.6) 9 (32.1) 25 (41) 1.02 (0.4-2.8)
Pro/Pro 3 (25) 2 (10.5) 6 (0.7-53.7) 7 (25) 2 (3.3) 9.9 (1.8-54.5) 1
Arg /Pro+ 9 (75) 11 (57.9) 3.3 (0.7-15.3) 16 (57.1) 27 (44.3) 1.7 (0.7-4.1)
Pro/Pro
Arg allele 12 (50) 25 (65.8) 1 33 (58.9) 93 (76.2) 1
Pro allele 12 (50) 13 (34.2) 1.9 (0.7-5.5) 23 (41.1) 29 (23.8) 2.2 (1.1-4.4) 2
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1P=0.009, 2P=0.029

Table 3 shows the association between TP53 variants and prostate cancer risk, stratified by the Gleason score among prostate cancer patients. No significant association was found between the Gleason score and TP53 genotype at codon 72 in these patients.

Table 3.

TP53 codon 72 genotype frequencies in prostate cancer patients stratified by Gleason score

Genotype Gleason score 6-7 n (%) Gleason score 8-10 n (%) OR (95% CI) p-value
Arg/Arg 4 (33.33) 11 (39.3) 1
Arg/Pro 4 (33.33) 11 (39.3) 0 0.7
Pro/Pro 4 (33.34) 6 (21.4) 1.8 (0.3-10) 0.8
Pro/Arg + Pro/Pro 8 (66.67) 17 (60.7) 1.3 (0.3-5.3) 0.9
Arg allele 12 (50) 33 (58.9) 1
Pro allele 12 (50) 23 39 (41.1) 1.4 (0.5-3.7) 0.6
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Discussion

The tumor suppressor gene TP53 plays a main role in the progression of human cancers (13, 14). The TP53 polymorphism at codon 72 has been found to be associated with susceptibility to cancers in different tumors (13, 15–17, 25, 26). Although several studies have investigated the association between TP53 variant and susceptibility to prostate cancer, their results are conflicting and inconclusive (15, 25, 26, 29, 33).

In this hospital-based case-control study, the association between TP53 gene polymorphism and the risk of prostate cancer was investigated in Iranian men. Our findings revealed that cases with Pro/Pro had a 6.8-fold increased risk of developing prostate cancer in comparison to those with Arg/Arg. Several studies have suggested an important role for TP53 codon 72 variant in the tu morgenesis and progression of prostate cancer (15, 25, 26). However, there are inconsistencies regarding the role of TP53 gene polymorphism in the development of prostate cancer. Wu et al. has shown that the proline genotype was 2.6 times more frequent than the arginine variant in prostate cancer patients and this difference was statistically significant (26). In another study, it is revealed that the Pro/Pro allele was correlated with a strikingly lower risk of prostate cancer (25).

This polymorphism happens in a proline-rich region of p53 that is important for the cell cycle arrest and apoptotic activities of this protein (34). It is shown that Arg/Arg variant of TP53 gene was a strikingly efficient suppressor of cellular transformation, an activity normally associated with p53’s apoptotic function. Therefore, individuals with Pro/Pro genotype may be more susceptible to the development of cancer (19, 35, 36).

Besides, the findings of this study did not support an association between age or Gleason score with TP53 genotype at codon 72 in prostate cancer patients. These results are consistent to previous studies showing no associations between TP53 codon 72 alleles and these factors in prostate cancer (26, 33, 37).

However, an association between the TP53 variant and the age > 65 years was found among PCa cases in comparison to BPH subjects. In other words, the TP53 Pro/Pro genotype was more prevalent in PCa patients compared to BPH subjects in age group > 65 years old. This difference likely arises from the small sample size in age group ≤ 65 years old. It is worth mentioning that this study has some limitations. One is the modest sample size of prostate cancer cases. Also, since the study population was hospital-based, healthy individuals were not investigated as a control group. However, by matching the age of PCa and BPH subjects we try to minimize the potential of this confounding factor.

Conclusion

There is an important difference in the frequency of TP53 codon 72 variants between PCa and BPH groups. Our findings suggest that TP53 codon 72 polymorphism may have an impact on the development of prostate cancer. Although the results suggest that the TP53 codon 72 genotype may confer more susceptibility to prostate cancer development, further studies are needed to confirm these results.

Ethical considerations

Ethical issues (Including plagiarism, Informed Consent, misconduct, data fabrication and/or falsification, double publication and/or submission, redundancy, etc) have been completely observed by the authors.

Acknowledgments

We thank the Pathology Laboratory of Sina Hospital in Tehran for providing clinical samples. This study has been funded and supported in part by Tehran University of Medical Sciences (TUMS), Grant no. 13510. It has also been part of a PhD thesis supported by Tehran University of Medical Sciences, Grant no. 240/3854. The authors declare that there is no conflict of interests.

References

  1. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D (2011). Global cancer statistics. CA Cancer J Clin, 61: 69–90. [DOI] [PubMed] [Google Scholar]
  2. Ferlay J, Shin HR, Bray F, Forman D, Mathers C, Parkin DM (2010). Estimates of worldwide burden of cancer in 2008: GLOBOCAN 2008. Int J Cancer, 127: 2893–2917. [DOI] [PubMed] [Google Scholar]
  3. IARC. Section of Cancer Information. Scientific Publications, Lyonn; 2008. [Google Scholar]
  4. Hayes RB, Pottern LM, Strickler H, Rabkin C, Pope V, Swanson GM, et al. (2000). Sexual behaviour, STDs and risks for prostate cancer. Br J Cancer, 82: 718–725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Casey G, Neville PJ, Plummer SJ, Xiang Y, Krumroy LM, Klein EA, et al. (2002). RNASEL Arg462Gln variant is implicated in up to 13% of prostate cancer cases. Nat Genet, 32: 581–583. [DOI] [PubMed] [Google Scholar]
  6. Downing SR, Russell PJ, Jackson P (2003). Alterations of p53 are common in early stage prostate cancer. Can J Urol, 10: 1924–1933. [PubMed] [Google Scholar]
  7. Jonsson BA, Adami HO, Hagglund M, Bergh A, Goransson I, Stattin P, et al. (2004). -160C/A polymorphism in the E-cadherin gene promoter and risk of hereditary, familial and sporadic prostate cancer. Int J Cancer, 109: 348–352. [DOI] [PubMed] [Google Scholar]
  8. Dong JT (2006). Prevalent mutations in prostate cancer. J Cell Biochem, 97: 433–447. [DOI] [PubMed] [Google Scholar]
  9. Urisman A, Molinaro RJ, Fischer N, Plummer SJ, Casey G, Klein EA, et al. (2006). Identification of a novel Gammaretrovirus in prostate tumors of patients homozygous for R462Q RNASEL variant. PLoS Pathog, 2: e25. [DOI] [PMC free article] [PubMed] [Google Scholar] [Retracted]
  10. Levine AJ, Momand J, Finlay CA (1991). The p53 tumour suppressor gene. Nature, 351: 453–456. [DOI] [PubMed] [Google Scholar]
  11. Lane DP (1992). Cancer. p53, guardian of the genome. Nature, 358: 15–16. [DOI] [PubMed] [Google Scholar]
  12. Zambetti GP, Quartin RS, Martinez J, Georgoff I, Momand J, Dittmer D, et al. (1991). Regulation of transformation and the cell cycle by p53. Cold Spring Harb Symp Quant Biol, 56: 219–225. [DOI] [PubMed] [Google Scholar]
  13. Hollstein M, Sidransky D, Vogelstein B, Harris CC (1991). p53 mutations in human cancers. Science, 253: 49–53. [DOI] [PubMed] [Google Scholar]
  14. Navone NM, Troncoso P, Pisters LL, Goodrow TL, Palmer JL, Nichols WW, et al. (1993). p53 protein accumulation and gene mutation in the progression of human prostate carcinoma. J Natl Cancer Inst, 85: 1657–1669. [DOI] [PubMed] [Google Scholar]
  15. Suzuki K, Matsui H, Ohtake N, Nakata S, Takei T, Nakazato H, et al. (2003). A p53 codon 72 polymorphism associated with prostate cancer development and progression in Japanese. J Biomed Sci, 10: 430–435. [DOI] [PubMed] [Google Scholar]
  16. Nadji SA, Mahmoodi M, Ziaee AA, Naghshvar F, Torabizadeh J, Yahyapour Y, et al. (2007). An increased lung cancer risk associated with codon 72 polymorphism in the TP53 gene and human papillomavirus infection in Mazandaran province, Iran. Lung Cancer, 56: 145–151. [DOI] [PubMed] [Google Scholar]
  17. Yoon YJ, Chang HY, Ahn SH, Kim JK, Park YK, Kang DR, et al. (2008). MDM2 and p53 polymorphisms are associated with the development of hepatocellular carcinoma in patients with chronic hepatitis B virus infection. Carcinogenesis, 29: 1192–1196. [DOI] [PubMed] [Google Scholar]
  18. Di V, V, Buonaguro L, Izzo F, Losito S, Botti G, Buonaguro FM, et al. (2011). TP53 and MDM2 gene polymorphisms and risk of hepatocellular carcinoma among Italian patients. Infect Agent Cancer, 6: 13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Thomas M, Kalita A, Labrecque S, Pim D, Banks L, Matlashewski G (1999). Two polymorphic variants of wild-type p53 differ biochemically and biologically. Mol Cell Biol, 19: 1092–1100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Galic V, Willner J, Wollan M, Garg R, Garcia R, Goff BA, et al. (2007). Common polymorphisms in TP53 and MDM2 and the relationship to TP53 mutations and clinical outcomes in women with ovarian and peritoneal carcinomas. Genes Chromosomes Cancer, 46: 239–247. [DOI] [PubMed] [Google Scholar]
  21. Toyama T, Zhang Z, Nishio M, Hamaguchi M, Kondo N, Iwase H, et al. (2007). Association of TP53 codon 72 polymorphism and the outcome of adjuvant therapy in breast cancer patients. Breast Cancer Res, 9: R34. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Granja F, Morari J, Morari EC, Correa LA, Assumpcao LV, Ward LS (2004). Proline homozygosity in codon 72 of p53 is a factor of susceptibility for thyroid cancer. Cancer Lett, 210: 151–157. [DOI] [PubMed] [Google Scholar]
  23. Yang W, Zhang Y, Tian X, Ning T, Ke Y (2008). p53 Codon 72 polymorphism and the risk of esophageal squamous cell carcinoma. Mol Carcinog, 47: 100–104. [DOI] [PubMed] [Google Scholar]
  24. Shen H, Zheng Y, Sturgis EM, Spitz MR, Wei Q (2002). P53 codon 72 polymorphism and risk of squamous cell carcinoma of the head and neck: a case-control study. Cancer Lett, 183: 123–130. [DOI] [PubMed] [Google Scholar]
  25. Henner WD, Evans AJ, Hough KM, Harris EL, Lowe BA, Beer TM (2001). Association of codon 72 polymorphism of p53 with lower prostate cancer risk. Prostate, 49: 263–266. [DOI] [PubMed] [Google Scholar]
  26. Wu HC, Chang CH, Chen HY, Tsai FJ, Tsai JJ, Chen WC (2004). p53 gene codon 72 polymorphism but not tumor necrosis factor-alpha gene is associated with prostate cancer. Urol Int, 73: 41–46. [DOI] [PubMed] [Google Scholar]
  27. Mittal RD, George GP, Mishra J, Mittal T, Kapoor R (2011). Role of functional polymorphisms of P53 and P73 genes with the risk of prostate cancer in a case-control study from Northern India. Arch Med Res, 42: 122–127. [DOI] [PubMed] [Google Scholar]
  28. Xu B, Xu Z, Cheng G, Min ZC, Mi Y, Zhang ZZ, et al. (2010). Association between polymorphisms of TP53 and MDM2 and prostate cancer risk in southern Chinese. Cancer Genet Cytogenet, 202: 76–81. [DOI] [PubMed] [Google Scholar]
  29. Salehi Z, Hadavi M (2012). Analysis of the codon 72 polymorphism of TP53 and human papillomavirus infection in Iranian patients with prostate cancer. J Med Virol, 84: 1423–1427. [DOI] [PubMed] [Google Scholar]
  30. Fredricks DN, Relman DA (1999). Paraffin removal from tissue sections for digestion and PCR analysis. Biotechniques, 26: 198–200. [DOI] [PubMed] [Google Scholar]
  31. Jalilvand S, Tornesello ML, Buonaguro FM, Buonaguro L, Naraghi ZS, Shoja Z, et al. (2012). Molecular epidemiology of human herpesvirus 8 variants in Kaposi's sarcoma from Iranian patients. Virus Res, 163: 644–649. [DOI] [PubMed] [Google Scholar]
  32. Storey A, Thomas M, Kalita A, Harwood C, Gardiol D, Mantovani F, et al. (1998). Role of a p53 polymorphism in the development of human papillomavirus-associated cancer. Nature, 393: 229–234. [DOI] [PubMed] [Google Scholar]
  33. Huang SP, Wu WJ, Chang WS, Wu MT, Chen YY, Chen YJ, et al. (2004). p53 Codon 72 and p21 codon 31 polymorphisms in prostate cancer. Cancer Epidemiol Biomarkers Prev, 13: 2217–2224. [PubMed] [Google Scholar]
  34. Pietsch EC, Humbey O, Murphy ME (2006). Polymorphisms in the p53 pathway. Oncogene, 25: 1602–1611. [DOI] [PubMed] [Google Scholar]
  35. Dumont P, Leu JI, Della PA, III, George DL, Murphy M (2003). The codon 72 polymorphic variants of p53 have markedly different apoptotic potential. Nat Genet, 33: 357–365. [DOI] [PubMed] [Google Scholar]
  36. Bergamaschi D, Samuels Y, Sullivan A, Zvelebil M, Breyssens H, Bisso A, et al. (2006). iASPP preferentially binds p53 proline-rich region and modulates apoptotic function of codon 72-polymorphic p53. Nat Genet, 38: 1133–1141. [DOI] [PubMed] [Google Scholar]
  37. Sun T, Lee GS, Oh WK, Pomerantz M, Yang M, Xie W, et al. (2010). Single-nucleotide polymorphisms in p53 pathway and aggressiveness of prostate cancer in a Caucasian population. Clin Cancer Res, 16: 5244–5251. [DOI] [PMC free article] [PubMed] [Google Scholar]

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