Abstract
Purpose
PIK3CA gene mutations have been identified in various malignancies, but the prevalence of specific mutations and their role in breast cancer development remain uncertain. This study aimed to investigate the clinicopathological significance and prognostic impact of PIK3CA mutations in breast cancer.
Methods
Five common PIK3CA mutations (H1047R and H1047L in exon 20, and E542K, E545K, and E545D in exon 9) were identified in breast cancer patients using amplification refractory mutation system (ARMS) allele-specific PCR. The study examined the relationships between these mutations and clinicopathologic factors, such as age, HR status, Her2 status, lymph node involvement, distant metastasis, clinicopathologic stage, and progression-free survival (PFS).
Results
A total of 40 female breast cancer patients were included in this study. Twenty mutations were detected, with 12 located in exon 20 and 8 in exon 9. The most frequent mutation was H1047R in exon 20, present in 11 patients (14.8%). PIK3CA mutations were more commonly observed in patients with HR + breast cancer (P < 0.05). No significant correlation was found between PIK3CA mutations and age, Her2 status, lymph node involvement, distant metastasis, clinicopathologic stage, or Ki-67 expression. Database analysis from the cBioPortal online database showed that the median PFS (95%CI) of the PIK3CA unaltered group [22.93 (17.25–48.30) months] was higher than that of the altered group [12.98 (8.18–18.14) months]. In this study, PIK3CA mutant-type group [13.00 (10.56–15.45) months] had lower median PFS than that of the wild-type group [25.00 (13.46–36.55) months] in all breast cancer patients, the difference was significant (P = 0.004). Further, compared with PIK3CA wild-type, mutant-type was associated with poor PFS in HR + and Her2 + breast cancer patients (P < 0.05). In addition, positive H1047R mutation in PIK3CA was associated with poor PFS of breast cancer (P < 0.05).
Conclusions
Our data and public database research show that the PIK3CA mutation is a significant gene change in breast cancer, and the PIK3CA mutation was associated with a shorter PFS in all, HR + and Her2 + breast cancer patients. This research confirmed the important role of PIK3CA in breast cancer.
Keywords: PIK3CA, H1047R mutation, Breast cancer, Poor survival
Introduction
Breast cancer, a highly heterogeneous and life-threatening disease, continues to pose a significant health challenge for women globally [1, 2]. The severity of breast cancer lies in its potential to metastasize to distant organs, often leading to poor prognosis and decreased survival rates [3]. Despite major progress in diagnosis, prevention, and treatment, challenges remain in treating aggressive breast cancer subtypes, and the prognosis for advanced-stage patients is still poor. Genetic mutations are crucial in the development of breast cancer, offering insights into the mechanisms behind tumor initiation and progression [4]. Notably, mutations in key genes like BRCA1, BRCA2, and TP53 are well-established risk factors for hereditary breast cancer, predisposing individuals to the development of this malignancy by compromising DNA repair mechanisms and promoting genomic instability, thus heightening susceptibility to tumorigenesis [5, 6]. Thus, comprehensive knowledge of genetic alterations in breast cancer is vital for identifying new therapeutic targets and enhancing patient outcomes.
The phosphatidylinositol-3-kinase catalytic alpha (PIK3CA) gene encoded protein constitutes the catalytic subunit p110α of class IA phosphoinositide 3-kinase, phosphoinositol 3-kinase (PI3K), whose main function is to catalyse 4, 5-PIP2 to 3, 4, 5-PIP3 and activate various intracellular target proteins as a second messenger [7]. PIK3CA is a crucial player in the PI3K/AKT signaling pathway that regulates essential cellular processes like growth, survival, and proliferation. It is estimated that PIK3CA mutations occur in approximately 30% of all breast cancer cases [8], with varying mutation rates across different molecular subtypes [9]. These mutations predominantly occur in specific regions of the p110α subunit, such as the kinase domain (H1047R) and helical domains (E542K and E545K) of the p110α subunit [10], and may evolve during the course of the disease progresses [11]. Evidence indicates that mutations in the PIK3CA gene induce continuous AKT activation through PI3K/AKT pathway, fostering aberrant cell growth and transformation while inhibiting apoptosis, thereby fueling the progression of breast cancer [12, 13]. Current treatment strategies targeting the PI3K pathway, such as PI3K inhibitors, have shown promise in preclinical studies and clinical trials [12]. Nevertheless, their effectiveness is frequently limited by the development of drug resistance and side effects. As breast cancer treatment shifts toward personalized medicine, it is crucial to clarify the prognostic significance of PIK3CA mutations across various breast cancer subtypes. Herein, we gathered specimens of primary or metastatic breast cancer lesions from patients at the Second Affiliated Hospital of Anhui Medical University between March 2018 and November 2023 to detect and observe PIK3CA mutation status. The correlations of PIK3CA status with clinical characteristics and patient outcomes were explored in a cohort of 40 female patients. Kaplan-Meier plot was further used to show the prognosis and survival curve of breast cancer patients with PIK3CA mutations. Overall, these results offered important insights into the clinical relevance of PIK3CA mutation in breast cancer.
Methods
Patients and tumor samples
We performed a retrospective study of breast cancer patients, gathering samples from primary or metastatic lesions at the Second Affiliated Hospital of Anhui Medical University from March 2018 to November 2023 for PIK3CA detection. Inclusion criteria: (1) All cases were pathologically confirmed as breast cancer; (2) Ensure that the obtained specimens meet the testing requirements; (3) The material selection meets ethical requirements; (4) Complete clinical data can be obtained. Exclusion criteria: (1) Double primary tumors (excluding double breast cancer); (2) Incomplete clinical data; (3) The specimens cannot meet the PIK3CA detection standards. This study received approval from the Ethics Committee of the Second Affiliated Hospital of Anhui Medical University (No. YX2023-206).
For detection, a continuous paraffin section was extracted and stained with HE. The distribution of the entire tumor tissue was evaluated under low magnification, marking any tumor-free areas with a crayon for exclusion from testing. High magnification was then used to select 5 fields of view on the slide: upper, lower, left, right, and middle. Thirty cells were counted continuously in each field, and the results were combined to calculate the average tumor cell content of the sample. A tumor cell count exceeding 20% was deemed a qualified specimen.
Pathological diagnosis: Pathological diagnosis involved analyzing breast core needle biopsy tissue or metastatic focus core needle biopsy tissue for invasive breast cancer at baseline. Immunohistochemical detection was used to determine histological grade, Her2 status, HR status, progesterone receptor status, and Ki-67 index. HR positive (HR+) tumors were defined as those with ER or PR present in at least 1% of tumor cells. Her2 status was classified based on immunohistochemistry results, with further FISH detection for Her2 (++) cases to confirm amplification.
DNA extraction and PIK3CA mutation detection
Human PIK3CA gene mutation detection kit (fluorescence PCR method) and paraffin embedded tissue DNA extraction kit were purchased from Xiamen Aide Biopharmaceutical Technology Co., Ltd. The micro-UV spectrophotometer was purchased from Thermo Fisher Scientific in the United States. The CFX96 fluorescence quantitative PCR instrument was purchased from BIO-RAD Company in the United States.
Pathological evaluation of paraffin section samples: involved the examination of formalin-fixed and paraffin-embedded tumors under a microscope (Leica) to analyze tumor cell content. A representative paraffin block containing at least 70% of tumor cells was selected for sectioning, and tumor tissue was scraped for DNA extraction.
The analysis focused on detecting mutations at 5 loci, E542K, E545D, E545K, H1047R, and H1047L. DNA extraction and ARMS-PCR reactions were performed using the manual column extraction method, strictly following the instructions of the Ed paraffin embedded tissue DNA extraction kit. The extracted DNA concentration was adjusted to 3.0 ng/µL, and samples were prepared according to the instructions of the AID Human PIK3CA Gene Mutation Detection Kit. The PCR reaction conditions were as follows: 95 °C for 5 min, followed by 25 cycles of 95 °C for 25 s, 64 ℃ for 20 s, and 72 ℃ for 20 s. This was followed by an additional 31 cycles of 93 °C for 25 s, 60 ℃ for 35 s, and 72 ℃for 20 s, with signal collection at 60 °C during the third stage. Target mutations in the samples were analyzed by determining the fractional cycle number at which levels reached a predefined cycle threshold (CT). Based on the CT values for the mutations, detection results were classified as either positive or negative for the presence of mutations.
Online database
In order to investigate PIK3CA expression in breast cancer, we accessed the cBioPortal database (http://www.cbioportal.org) to examine the relationship between PIK3CA mutation status and progression-free survival (PFS). Corresponding Kaplan-Meier plots were generated, and results are presented with P values obtained from the log-rank test.
Statistical analysis
Chi-square tests were conducted to analyze the relationship between PIK3CA gene mutations and clinical characteristics. The Kaplan-Meier method estimated progression-free survival, while the log-rank test compared survival distributions between groups. All analyses were performed using SPSS 26.0 software. The Kaplan-Meier curves were drawn using the ggplot2 package in R (version 4.2.1). The P-value of less than 0.05 was deemed statistically significant.
Results
Online database analysis
Before analyzing the clinical samples, we evaluated the relationship between PIK3CA gene changes (DNA mutations) and prognosis in cancer patients using the publicly available bioinformatics database named cBioPortal (http://www.cbioportal.com). Figure 1A shows the analysis of PIK3CA alteration frequency in different tumor types. In breast cancer, “mutation” accounted for the highest alteration frequency of PIK3CA, followed by “amplification”. Figure 1B shows the mutational landscape and the mutation sites of PIK3CA according to cBioPortal database. Missense mutation of PIK3CA was the main genetic alteration type, furthermore, H1047R and E545K were frequent mutation sites. In cBioPortal database, 135 patients with breast cancer were used to evaluate the relationship between PIK3CA alteration and PFS using Kaplan-Meier estimation. Among them, 41 cases (30.4%, 41/135) showed PIK3CA alteration. Figure 1C shows that PIK3CA alterations in cancer are associated with poor PFS outcomes. The median PFS of 41 breast cancer patients in the PIK3CA altered group was 12.98 months (95%CI: 8.18–18.14 months), while that of 94 patients in the PIK3CA unaltered group was 22.93 months (95%CI: 17.25–48.30 months).
Fig. 1.
Analysis based on cBioPortal database. (A) Analysis of LIFR alteration frequency in pan-cancer, and the red rectangle had marked breast cancer. (B) The mutational landscape and the mutation sites of PIK3CA, the most common mutation sites were H1047R and E545K. (C) Kaplan-Meier plots for progression-free survival in 135 breast cancer patients from cBioPortal. Data were generated from http://cbioportal.org
Baseline characteristics of included patients
Forty patients with breast cancer were included in this study, all of whom were female, aged 29–81 years, with a median age of 54 years. At the end of the follow-up, 18 patients survived and 22 had died. Among all enrolled patients, 75.0% (30/40) were HR+, 25.0% (10/40) were HR-, 57.5% (23/40) were classified as Her2+, and 42.5% (17/40) were classified as Her2-, based on routine pathological classification. 22.5% (9/40) were in stage III, and 77.5% (31/40) were in stage IV. 62.5% (26/40) patients had lymph node metastasis (LN+), while 37.5% (14/40) patients did not (LN-). 65.0% (26/40) had distant metastasis, while 35% (14/40) patients did not. We found no correlation between baseline characteristics and survival status (all P > 0.05). More detailed information is presented in Table 1.
Table 1.
Clinical characteristics of 40 patients.
| Characteristics | Total (%) | Alive (%) | Deceased (%) | χ2 | P value |
|---|---|---|---|---|---|
| Age (years) | |||||
| ≤ 55 | 25 (62.5) | 11 (57.9) | 14 (66.7) | 0.327 | 0.567 |
| > 55 | 15 (37.5) | 8 (42.1) | 7 (33.3) | ||
| HR status | |||||
| HR- | 10 (25.0) | 5 (26.3) | 5 (23.8) | 0.033 | 0.855 |
| HR+ | 30 (75.0) | 14 (73.7) | 16 (76.2) | ||
| Her2 status | |||||
| Her2- | 17 (42.5) | 7 (36.8) | 10 (47.6) | 0.474 | 0.491 |
| Her2+ | 23 (57.5) | 12 (63.2) | 11 (52.4) | ||
| Clinicopathologic stage | |||||
| III | 9 (22.5) | 4 (21.1) | 5 (23.8) | 0.043 | 0.835 |
| IV | 31 (77.5) | 15 (78.9) | 16 (76.2) | ||
| Lymph node status | |||||
| LN (-) | 15 (37.5) | 5 (26.3) | 10 (47.6) | 1.931 | 0.165 |
| LN (+) | 25 (62.5) | 14 (73.7) | 11 (52.4) | ||
| Distant metastasis | |||||
| M (-) | 14 (35.0) | 8 (42.1) | 6 (28.6) | 0.803 | 0.370 |
| M (+) | 26 (65.0) | 11 (57.9) | 15 (71.4) | ||
| Ki−67 (%) | |||||
| ≤ 30 | 22 (55.0) | 12 (63.2) | 10 (47.6) | 0.973 | 0.324 |
| > 30 | 18 (45.0) | 7 (36.8) | 11 (52.4) |
Abbreviations: LN, lymph node; M, metastasis
PIK3CA mutations were found in breast cancer
Among the 40 female patients, PIK3CA mutations in exons 9 and 20 were detected using ARMS-PCR technology. Overall, 20 patients (50.0%) had a single mutation in the analyzed regions. Eight mutations were identified in the helical domain (E5425K, exon 9), while 12 mutations were found in the kinase domain—11 were H1047R mutations and one was H1047L (exon 20). The predominant mutation, or “hot spot,” was H1047R in the kinase domain (exon 20). No mutations were observed in E542K or E545D. The frequency and distribution of these mutations are detailed in Table 2.
Table 2.
Frequency of each PIK3CA mutation type in breast cancer.
| Characteristics | Total (%) | Exon 20 | Exon 9 | ||||
|---|---|---|---|---|---|---|---|
| H1047R (%) | H1047L (%) |
E542K (%) | E545K (%) | E545D (%) | |||
| Number of mutations | 20 (50.0)a | 11 (27.5) | 1 (2.5) | 0 (0.0) | 8 (20.0) | 0 (0.0) | |
| Age (years) | |||||||
| ≤ 55 | 14 (35.0) | 8 (20.0) | 0 (0.0) | 0 (0.0) | 6 (15.0) | 0 (0.0) | |
| > 55 | 6 (15.0) | 3 (7.5) | 1 (2.5) | 0 (0.0) | 2 (5.0) | 0 (0.0) | |
| HR status | |||||||
| HR- | 1 (5.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (2.5) | 0 (0.0) | |
| HR+ | 19 (47.5) b | 11 (27.5) | 1 (2.5) | 0 (0.0) | 7 (17.5) | 0 (0.0) | |
| Her2 status | |||||||
| Her2- | 10 (25.0) | 7 (17.5) | 0 (0.0) | 0 (0.0) | 3 (7.5) | 0 (0.0) | |
| Her2+ | 10 (25.0) | 4 (10.0) | 1 (5.0) | 0 (0.0) | 5 (12.5) | 0 (0.0) | |
| Clinicopathologic stage | |||||||
| III | 3 (7.5) | 1 (2.5) | 0 (0.0) | 0 (0.0) | 2 (5.0) | 0 (0.0) | |
| IV | 17 (42.5) | 10 (25.0) | 1 (2.5) | 0 (0.0) | 6 (15.0) | 0 (0.0) | |
| Lymph node status | |||||||
| LN (-) | 8 (20.0) | 3 (7.5) | 1 (2.5) | 0 (0.0) | 4 (10.0) | 0 (0.0) | |
| LN (+) | 12 (30.0) | 8 (20.0) | 0 (0.0) | 0 (0.0) | 4 (10.0) | 0 (0.0) | |
| Distant metastasis | |||||||
| M (-) | 5 (7.5) | 3 (7.5) | 0 (0.0) | 0 (0.0) | 2 (5.0) | 0 (0.0) | |
| M (+) | 15 (22.5) | 8 (20.0) | 1 (2.5) | 0 (0.0) | 6 (15.0) | 0 (0.0) | |
| Ki−67 (%) | |||||||
| ≤ 30 | 12 (30.0) | 8 (20.0) | 1 (2.5) | 0 (0.0) | 3 (7.5) | 0 (0.0) | |
| > 30 | 8 (20.0) | 3 (7.5) | 0 (0.0) | 0 (0.0) | 5 (12.5) | 0 (0.0) | |
Note: a Each sample had only a single mutation; bP < 0.05.
Abbreviations: LN, lymph node; M, metastasis.
PIK3CA mutation associated with HR status
We examined the clinical characteristics of breast cancer patients based on PIK3CA mutation status (Tables 2 and 3). The mutant-type group was more commonly associated with HR-positive tumors compared to the PIK3CA wild-type group, with 19 point mutations found in HR + and 1 point mutation in HR- patients (P = 0.030). No significant associations were observed between PIK3CA mutation status and age, Her2 status, distant metastasis, lymph node status, distant metastasis, or Ki-67 (all P > 0.05).
Table 3.
Clinical characteristics according to PIK3CA mutation status in breast cancer.
| Characteristics | Total (%) | PIK3CA mutation status | χ2 | P value | |
|---|---|---|---|---|---|
| Wild (%) | Mutant (%) | ||||
| Age (years) | |||||
| ≤ 55 | 25 (62.5) | 11 (55.0) | 14 (70.0) | 0.960 | 0.327 |
| > 55 | 15 (37.5) | 9 (45.0) | 6 (30.0) | ||
| HR status | |||||
| HR- | 10 (25.0) | 9 (45.0) | 1 (5.0) | 8.533 | 0.003b |
| HR+ | 30 (75.0) | 11 (55.0) | 19 (95.0) | ||
| Her2 status | |||||
| Her2- | 17 (42.5) | 7 (35.0) | 10 (50.0) | 0.921 | 0.337 |
| Her2+ | 23 (57.5) | 13 (65.0) | 10 (50.0) | ||
| Clinicopathologic stage | |||||
| III | 9 (22.5) | 6 (30.0) | 3 (15.0) | 1.290 | 0.256 |
| IV | 31 (77.5) | 14 (70.0) | 17 (85.0) | ||
| Lymph node status | |||||
| LN (-) | 15 (37.5) | 7 (35.0) | 8 (40.0) | 0.107 | 0.744 |
| LN (+) | 25 (62.5) | 13 (65.0) | 12 (60.0) | ||
| Distant metastasis | |||||
| M (-) | 14 (35.0) | 9 (45.0) | 5 (25.0) | 1.758 | 0.185 |
| M (+) | 16 (65.0) | 11 (55.0) | 15 (75.0) | ||
| Ki−67 (%) | |||||
| ≤ 30 | 22 (55.0) | 10 (50.0) | 12 (60.0) | 0.404 | 0.525 |
| > 30 | 18 (45.0) | 10 (50.0) | 8 (40.0) | ||
Notes: a χ2 test used for binary/categorical variables; bP < 0.05.
Abbreviations: LN, lymph node; M, metastasis.
PIK3CA mutation and PFS
We evaluated the impact of PIK3CA mutations on PFS in breast cancer patients, as shown in Table 4. The median follow-up duration for the cohort was 19 months (range: 0–47 months). Patients with PIK3CA mutations had a significantly shorter median PFS of 13.00 months (95% CI: 8.87–19.13 months), compared to about 25.00 months (95% CI: 13.46–36.55 months) for those with PIK3CA wild-type breast tumors, with a significant difference observed (P = 0.004) (Fig. 2A). In HR + breast cancer patients, there was a significant difference between the median PFS of mutant-type group (13.00, 95%CI:10.56–15.45 months) and the median PFS of wild-type group (25.00, 95%CI:17.99–32.01 months)(P = 0.022)(Fig. 2B). Survival analysis was not performed in HR- breast cancer patients, due to the limited number of included patients. In Her2 + breast cancer patients, there was a significant difference between the median PFS of mutant-type group (13.00, 95%CI:4.65–21.36 months) and the median PFS of wild-type group (39.00, 95%CI: 22.56–55.46 months)(P = 0.003)(Fig. 2C). No significant association was found between the median PFS of the mutant-type and wild-type groups in Her2- breast cancer (P = 0.442). In this study, the H1047R mutation was the most common site. H1047R mutations were linked to shorter PFS, reaching statistical significance (P = 0.006) (Fig. 2D). The median PFS for H1047R (+) patients was 12.00 months (95% CI: 0.00-24.67 months), compared to 20 months (95% CI: 9.09–30.91 months) for H1047R (-) patients.
Table 4.
Prognosis of PIK3CA mutation in different types of breast cancer.
| Cancer type | No. of total cases | No. of events |
Median PFS (95%CI) | P value | |
|---|---|---|---|---|---|
| Wild | Mutant | ||||
| All breast cancer | 40 | 22 | 25.00 (13.46–36.55) | 13.00 (8.87–19.13) | 0.004 |
| HR + breast cancer | 30 | 17 | 25.00 (17.99–32.01) | 13.00 (10.56–15.45) | 0.022 |
| HR- breast cancer | 10 | 5 | NA | NA | NA |
| Her2 + breast cancer | 23 | 12 | 39.00 (22.56–55.46) | 13.00 (4.65–21.36) | 0.003 |
| Her2- breast cancer | 17 | 10 | 12.66 (5.83–19.50) | 12.00 (0.61–23.38) | 0.442 |
Abbreviations: PFS, progression free survival; CI, confidence interval
Fig. 2.
Kaplan–Meier curves for the effect of PIK3CA mutation status on PFS in all breast cancer (A), HR + breast cancer (B), and Her2 + breast cancer patients (C). The Kaplan–Meier curves for the effect of PIK3CA mutation at the H1047R site in all breast cancer patients (D).
Discussion
Breast cancer is a heterogeneous disease characterized by diverse genetic alterations, including mutations in the PIK3CA gene [9, 14]. According to existing literature, the mutation rate of PIK3CA in breast cancer ranges from 20-35.7% [8, 15], with varying rates in specific subtypes such as HR+/Her2-, Her2+, and triple-negative breast cancer (28–47%, 23–33%, and 8–25%, respectively) [9]. While our findings revealed a mutation rate of 50.0% in the total samples, with the highest incidence observed in the HR + subgroup. The common mutation sites were H1047R, E545K, E542K, N345K, and H1047L [16, 17], with the highest mutation frequency in HR+/Her2- [8]. Notably, consistent with the previous study, the predominant mutations identified in patients of this study were located at H1047R. Meanwhile, PIK3CA mutation was associated with a shorter PFS in all, HR+, Her2 + and H1047R positive breast cancer patients.
PI3K is the main hub of multiple signaling pathways, and its excessive activation can lead to disruption of signaling pathways such as AKT/mTOR [18]. The mutation of the PIK3CA gene was an early event in breast cancer that facilitated its occurrence and progression [19]. The study found that the abnormal activation of PI3K/AKT/mTOR (PAM) signaling pathway was the most common pathogenic factor of breast cancer, and was related to poor prognosis, and it was also one of the main reasons for tumor cell resistance to treatment [20, 21]. The standardized treatment of advanced HR + breast cancer includes endocrine therapy, but about 50% of HR + breast cancer patients have disease progression due to endocrine therapy resistance, and the emergence of drug resistance in these patients is usually related to gene mutations such as PIK3CA [22]. Research indicated that abnormal activation of the PI3K pathway can cause ER phosphorylation, increase the expression of ER-related regulatory genes, and ultimately result in primary or acquired resistance to endocrine therapy [23, 24]. According to reports, PIK3CA mutations are associated with resistance to Her2 and endocrine therapy in many preclinical cell lines and xenograft models. In Her2 positive breast cancer, some preclinical studies reported that PIK3CA mutation was related to the drug resistance of trastuzumab to Her2 blocking [25, 26]. Another study verified that these mutations can lead to resistance against trastuzumab, though breast cancer cell lines with E545K and H1047R-Her2 overexpression showed sensitivity to the PI3K inhibitor GDC-0941 [27]. PI3K is an important target gene downstream of the Her2 signaling pathway, and inhibiting abnormal activation of this signal may be an effective strategy to prevent Her2 targeted therapy resistance.
The impact of PIK3CA mutation on the prognosis of breast cancer patients has been a hot topic in recent years. Fillbrunn et al. performed a meta-analysis to group 3219 patients with HR+/Her2- metastatic breast cancer according to whether the PIK3CA gene was mutated or not, and analyzed PFS. The results showed that the median PFS of patients with PIK3CA mutation was less than that of patients with PIK3CA wild group (-1.8 months, 95% CI: -3.4 to -0.1 months), indicating that PIK3CA mutation had negative value for the prognosis of patients with HR+/Her2- metastatic breast cancer. Similarly, Navid et al. confirmed that PIK3CA mutation was an independent risk factor for PFS in breast cancer patients through meta-analysis (HR = 2.05, 95% CI = 1.30–3.25, I2 = 0%) [28]. In a retrospective study of ER+/Her2- primary breast cancer patients who recurred within 5 years after continuous endocrine therapy, the existence of PIK3CA mutation was significantly related to lymph node involvement, which suggested that tumors with PIK3CA mutation might be more invasive and spread to lymph nodes [29]. Further, this study also showed that during continuous endocrine therapy, the mutation was more frequent in the recurrent group (48%) than in the primary tumor group (40%) [29]. André et al. carried out a phase III clinical trial involving 572 patients, and reported that the combination of PI3Kα-specific inhibitor Alpelisib in combination with fulvestrant significantly prolonged the PFS of patients with PIK3CA mutation, HR positive, Her2 negative advanced breast cancer [30]. These all suggest that PIK3CA mutation status testing should be performed in late stage tumor specimens for PI3K inhibitor treatment. In the future, more research is needed to expand the cohort to detect the PIK3CA mutation status of breast cancer patients, thus helping to optimize their treatment and subsequent evaluation. In conclusion, PIK3CA mutation is an important target for potential treatment of breast cancer, and its accurate detection has brought new opportunities and challenges for breast molecular pathology [31, 32].
Although the study offers valuable insights, there were several limitations to note. First, although this study provides preliminary exploratory data, the small sample size may restrict the generalizability of the results, and larger scale confirmatory studies are still needed to support this hypothesis. Second, due to the fact that the data is collected based on historical records or existing cases, it is not possible to randomly select samples, which may result in certain populations being over or under represented in the study, affecting the extrapolation of the results. Furthermore, the study focused on specific molecular and clinical parameters, while other potential prognostic factors in breast cancer patients may influence outcomes. Additionally, the reliance on puncture specimens makes it difficult to acquire pre- and post-treatment samples, hindering the ability to assess the direct impact of treatment methods on mutations. Consequently, it is crucial to adopt an integrated approach that combines treatment responses with mutation results to infer the potential influence of mutations on treatment outcomes. Although a higher proportion of patients with mutant PIK3CA appeared to have metastases compared to the wild type, the difference did not reach statistical significance (p = 0.185). This may be due to the limited sample size of our study, which could restrict its statistical power. Future studies with larger sample sizes are warranted to clarify this association and further investigate the clinical implications of PIK3CA mutations in metastasis. PIK3CA mutation is population dependent, and this difference may be closely related to factors such as the genetic background and lifestyle of the population. Given that this is a single-center study conducted in Anhui, China, the findings should be interpreted with caution when applying them to other populations such as Europe. Further multicenter studies involving diverse populations are warranted to validate our results.
Conclusion
In conclusion, our study indicated that PIK3CA mutations were linked to poor prognosis in breast cancer, which may carry significant clinical implications. Substantial research has been directed toward identifying PI3K/AKT pathway inhibitors for breast cancer and other malignancies. Further studies are required to confirm the connection between PIK3CA mutations and the PI3K/AKT pathway, as well as to clarify the specific mechanisms through which these mutations influence tumor behavior. A deeper understanding of the molecular mechanisms in breast cancer will pave the way for the development of new, personalized anticancer therapies.
Author contributions
Conception/Design: MY, ZZ, WG, XL; Financial support: YK, FL; Administrative support: YK, FL; Provision of study materials: XX, JL, LW; Collection/assembly of data: MY, WG, XL; Data analysis: MY, ZZ, WG; Manuscript writing: MY, ZZ, WG. All authors read and approved the final manuscript.
Funding
This work is supported by the Institute of Energy, Hefei Comprehensive National Science Center (Grant No. GXXT-2022-003, 21KZS202) and Anhui Province Key Research and Development Plan (Grant No. 2022e07020038).
Data availability
Data is provided within the manuscript or supplementary information files.
Declarations
Ethical approval and consent to participate
All procedures followed the ethical guidelines of the Declaration of Helsinki in 1964 and its subsequent amendments. The study received approval from the Ethics Committee of the Second Affiliated Hospital of Anhui Medical University (No. YX2023-206). This study declared that informed consent has been obtained from all participating patients.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Min Yan, Zhiqiang Zong contributed equally to this work.
Contributor Information
Min Yan, Email: 603377877@qq.com.
Yuan Kong, Email: doctorkong@163.com.
Fanfan Li, Email: fflahykdx@163.com.
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Data Availability Statement
Data is provided within the manuscript or supplementary information files.