RAD51 135G>C polymorphism and breast cancer risk: a meta-analysis

The influence of RAD51 (rs1801320) on breast cancer risk: an updated meta-analysis

BACKGROUND

DNA repair mechanisms, particularly RAD51-mediated homologous recombination repair, play a crucial role in breast cancer development, with the rs1801320 (135G > C) polymorphism showing conflicting associations across studies. This meta-analysis aimed to assess the relationship between RAD51 rs1801320 polymorphism and breast cancer susceptibility.

METHOD

We systematically searched PubMed and Web of Science databases through August 15, 2024, and included 16 case-control studies comprising 4743 breast cancer cases and 4448 controls, analyzing various genetic models using R Studio.

RESULTS

Our results revealed significant associations in several genetic models: the allele contrast model (C vs. G) showed an increased risk (OR = 1.37, 95% CI: 1.04-1.80, p = 0.0249. The recessive model (CC vs. CG + GG) demonstrated a strong risk association (OR = 2.68, 95% CI: 1.55-4.61, p = 0.00038), while the dominant model (CC + CG vs. GG) showed no significant association (OR = 1.12, 95% CI: 0.98-1.28, p = 0.1037). Pairwise comparisons revealed the CC genotype as a substantial risk factor, particularly in CC vs. GG (OR = 2.31, 95% CI: 1.58-3.37, p = 0.00001) and CC vs. CG (OR = 2.97, 95% CI: 1.53-5.77, p = 0.00128) comparisons. Most models showed moderate to high heterogeneity (I2 = 30-93%), though publication bias was detected in some analyses.

CONCLUSION

This comprehensive meta-analysis is larger than previous studies and provides robust evidence that the RAD51 rs1801320 CC genotype significantly increases breast cancer risk, particularly in recessive and homozygous comparison models, suggesting potential implications for cancer risk assessment and therapeutic strategies targeting DNA repair mechanisms.

Meta-analysis of the association between overexpression of RAD51 family genes and prognosis and clinical features in breast cancer

The RAD51 family of genes play a crucial role in the repair of DNA damage, and increasing evidence suggests a close link between the aberrant expression of RAD51 family genes and the development of breast cancer. However, their prognostic and clinical relevance remains subjects of ongoing debate. This study aims to systematically investigate the relationship between the overexpression of RAD51 family genes and breast cancer prognosis, as well as their association with clinicopathological characteristics, through a comprehensive meta-analysis. PubMed, EMBASE, OVID, Web of Science, Scopus, and Cochrane Library were systematically searched for relevant studies published up to August 25, 2024. Two independent researchers screened the literature according to predefined inclusion and exclusion criteria and extracted relevant data. Statistical analyses were conducted using the Meta package in R 4.2.2. Thirteen studies comprising 20,222 breast cancer patients were included. High expression of RAD51 family genes was associated with poorer overall survival (OS) [HR = 1.305, 95%CI (1.145-1.488), P < 0.01], disease-free survival/distant metastasis-free survival (DFS/DMFS) [HR = 1.588, 95%CI (1.208-2.089), P < 0.01], and disease-specific survival (DSS) [HR = 1.403, 95%CI (1.066-1.846), P = 0.02]. In addition, subgroup analyses further showed that high RAD51 expression was associated with worsened OS [HR = 1.475, 95%CI (1.275-1.706), P < 0.01], DFS [HR = 1.584, 95%CI (1.133-2.215), P < 0.01] and progression-free survival (PFS) [HR = 2.439, 95%CI (1.172-5.075), P = 0.02]. In contrast, high expression of RAD51 paralogs was linked to improved PFS prognosis [HR = 0.870, 95%CI (0.797-0.949), P < 0.01]. Regarding clinical characteristics, high expression of RAD51 family genes was significantly associated with human epidermal growth factor receptor 2 (HER2) positivity [OR = 1.782, 95%CI (1.328-2.392), P < 0.01]. The overexpression of RAD51 family genes is correlated with unfavorable prognosis in breast cancer and exhibits a strong association with HER2-positive subtypes. These findings underscore the potential of RAD51 family genes as prognostic biomarker and therapeutic targets in breast cancer management.

Association of RAD51, XRCC1, XRCC2, and XRCC3 Polymorphisms with Risk of Breast Cancer

Background: DNA repair genes are among the low-penetrance genes implicated in breast cancer. However variants of DNA repair genes may alter their protein function thus leading to carcinogenesis. Breast cancer is the most common cancer among women in India. The aim of the present study was to identify association, if any, of single nucleotide polymorphisms (SNP's) in four genes involved in DNA repair pathways including, RAD51 rs1801320, XRCC1 rs25487, XRCC2 rs3218536, and XRCC3 rs861539 with the risk of breast cancer. Materials and Methods: In this case-control study 611 female subjects (311 breast cancer patients and 300 healthy controls) were screened for four SNPs using polymerase chain reaction-restriction fragment length polymorphism analyses. Multifactor dimensionality reduction (MDR) analysis was performed to estimate the gene-gene interaction. Protein-protein interaction network analysis were studied using the STRING database. Results: The GC genotype (p = 0.018) and the combined GC+CC (p = 0.03) genotypes of RAD51 rs1801320 were significantly associated with reduced risk of breast cancer. The CT genotype (p = 0.0001), the combined CT+TT genotypes (p = 0.0002), and the T allele (p = 0.0019) of XRCC3 rs861539 polymorphism were associated with reduced risk of the breast cancer. No association of XRCC1 rs25487 and XRCC2 rs3218536 polymorphisms with breast cancer was observed. MDR analysis indicated a positive interaction between XRCC3 and XRCC2. String network analysis showed that the RAD51, XRCC1, XRCC2, and XRCC3 proteins are in strong interaction with each other and other breast cancer-related proteins such as BRCA2. Conclusion: RAD51 rs1801320 and XRCC3 rs861539 polymorphisms were associated with reduced risk of breast cancer. There is evidence of positive interactions among XRCC1, XRCC2, XRCC3, and RAD51.

Association between RAD51, XRCC2 and XRCC3 gene polymorphisms and risk of ovarian cancer: a case control and an in silico study

Homologous recombination (HR) is one of the important mechanisms in repairing double-strand breaks to maintain genomic integrity and DNA stability from the cytotoxic effects and mutations. Various studies have reported that single nucleotide polymorphisms (SNPs) in the HR-associated genes may have a significant association with ovarian cancer (OCa) risk but the results were inconclusive. In the present study, five polymorphisms of HR-associated genes (RAD51, XRCC2 and XRCC3) were genotyped by allelic discrimination assay in 200 OCa cases and 200 healthy individuals. The association with OCa risk was evaluated by unconditional logistic regression analyses. The results revealed that the mutant allele in both rs1801320 (CC) and rs1801321 (TT) of RAD51 gene was associated with increased risk of OCa (odds ratio [OR] 3.79, 95% confidence interval [CI] 1.21-11.78, p = 0.014 and OR 1.61, 95% CI 1.06-2.45, p = 0.025, respectively). Moreover, a significant association of TT allele (OR 4.68, 95% CI 1.27-17.15, p = 0.011) of rs3218536 of XRCC2 gene with OCa was observed. Stratified analysis results showed that patients with early menarche and stages 3 and 4 were found to be associated with rs1801321 of RAD51 gene and rs1799794 of XRCC3 gene. In silico analysis predicted that the two missense SNPs (rs3218536 and rs1799794) were found to have an impact on the protein structure, stability and function. The present study suggested that RAD51 and XRCC2 gene polymorphisms might have an impact on the OCa risk in the South Indian population. However, studies with a larger sample and on different populations are needed to support the conclusions.

Polymorphism of DNA Repair Genes via Homologous Recombination (HR) in Ovarian Cancer

Ovarian cancer is one of the most common types of cancer in women. The repair system via homologous recombination repairs double-strand breaks (DSB) of DNA, which are the most mortal for cell, out of all DNA damages. The genes, which encode the double-strand break repairing proteins, are highly polymorphic and, taking into account the significance of the repaired defects for cancer development, it seems important to learn the role of the polymorphisms in ovarian cancer development. The aim of the study was to determine the relationship between DNA repair genes via homologous recombination (HR) and modulation of the risk of ovarian cancer. The following polymorphisms were analysed: XRCC3-Thr241Met (rs861539), XRCC2--41657C/T (rs718282), XRCC2-Arg188His (rs3218536), BRCA1-Q356R (rs1799950) and RAD51-135 G/C (rs1801320). The study group included 600 patients with ovarian cancer and 600 healthy controls. The PCR-RFLP (PCR-based restriction fragment length polymorphism) technique was applied for polymorphism analysis. Allele XRCC3-241Met (OR 0.85, 95%CI 0.72-0.99, p < 0.045), XRCC2-41657 T (OR 1.67, 95% CI 1.42-1.96, p < .0001), BRCA1-356R (OR 1.61; % CI 1.37-1.90, p < .0001) and RAD51-135C (OR 5.16; 95% CI 4.29-6.20, p < .0001) strongly correlated with the neoplastic disease. No relationship was observed between the studied polymorphisms and the cancer progression stage according to FIGO classification. The results indicate that polymorphisms of DNA repair genes via homologous recombination may be associated with the incidence of ovarian cancer. Further research on larger groups is warranted to determine the influence of above-mentioned genetic variants on ovarian cancer risk.

Polymorphism of DNA repair genes in breast cancer

Aim

The aim of the study was to determine the relationship between single nucleotide polymorphisms (SNPs) of DNA repair genes and modulation of the risk of breast cancer. The following SNPs were analysed: XRCC1-Arg399Gln (rs25487), hMSH2-Gly322Asp (rs4987188), XRCC2-Arg188His (rs3218536), XPD- Lys751Gln (rs13181), RAD51--4719A/T (rs2619679) and RAD51--4601A/G (rs5030789).

Material and Methods

The study included n = 600 patients: 300 with breast cancer and 300 healthy controls. The HRM (High-Resolution Melter) technique was applied for polymorphism analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each genotype and allele.

Results

Statistically significant correlations were identified between four single nucleotide polymorphisms and the breast cancer risk: XRCC1-Arg399Gln, hMSH2-Gly322Asp, XPD- Lys751Gln and RAD51--4719A/T. Allele XRCC1-Gln (OR 6.37; 95% CI 4.86-8.35, p < .0001), hMSH2-Asp (OR 4.41; 95% CI 3.43-5.67, p < .0001), XPD -Gln (OR 2.56; 95% CI 2.02-3.25, p < .0001) and RAD51-T genes (OR 1.44; 95% CI 1.15-1.80, p = 0.002) strongly correlated with breast carcinoma. No relationship was observed between the studied polymorphisms and the cancer progression grade according to Scarf-Bloom-Richardson classification.

Conclusions

The results implies that polymorphisms of DNA repair genes may be associated with breast cancer occurrence.

Homozygous T172T and Heterozygous G135C Variants of Homologous Recombination Repairing Protein RAD51 are Related to Sporadic Breast Cancer Susceptibility

Breast cancer (BC) is the most common cancer and the second leading cause of death among women worldwide. Only 10% of BC cases have been related to genetic predisposition. Rad51, a homologous recombination (HR) protein plays an important role in HR in meiosis and repairing DNA double-strand breaks. Expression of RAD51 may be a predictive biomarker in certain types of cancers. The exact mechanisms involved in the regulation of RAD51 expression are not fully understood, but certain transcription factors have been suggested to be the tuning mechanism of its expression. In this study, we propose that polymorphisms in the 5'-UTR promoter region of the RAD51 gene are prognostic factors for BC development. Direct sequencing of 106 samples from sporadic BC patients and 54 samples from a control group was performed. FFPE samples were the choice of sample collection, which might be a limitation of our study. Homologous variant T172T alone was found to be significantly associated with BC risk (OR 3.717, 95% CI 2.283-6.052, p < 0.0001). On the other hand, heterozygous G135C did not show any significant relationship with risk of sporadic BC (OR 1.598, 95% CI 0.5638-4.528, p > 0.05). Moreover, both variants; homozygous T172T and heterozygous G135C together; showed a significant relationship with sporadic BC susceptibility.

RAD51 135G>C substitution increases breast cancer risk in an ethnic-specific manner: a meta-analysis on 21,236 cases and 19,407 controls

RAD51 is a homolog of bacterial RecA protein, which plays an important role in preserving stability of the genome. RAD51 interacts with BRCA1 and BRCA2 for homologous recombination repair. A functional polymorphism (135G > C) in the RAD51 gene has been a subject of great interest, which is evidenced by at least 28 case-control studies and eight meta-analyses undertaken on this polymorphism till now. We undertook a meta-analysis on RAD51 135G > C data for 21236 cases and 19407 controls pooled from 28 studies on breast cancer in women. Pooled data analysis suggested a significant association of the substitution with breast cancer in the recessive model (GG + GC versus CC) and in the co-dominant models comparing GG versus CC and GC versus CC. Analysis of the results suggested that ‘CC’ genotype is a significant breast cancer risk factor in comparison to ‘GG’ and ‘GC’ genotypes. We also undertook pooled analyses on different ethnic groups and found that ‘CC’ was a strong risk factor in Caucasians, but not in East-Asians and populations of mixed ethnicity. In conclusion, the RAD51 135G > C substitution in the homozygous form (CC) increases the risk of breast cancer in an ethnic-specific manner.

The RAD51 135G>C polymorphism is related to the effect of adjuvant therapy in early breast cancer

PURPOSE

RAD51, a central player in the response to DNA damage, has been suspected to contribute to tumour resistance to therapy. A single-nucleotide polymorphism, RAD51 135G>C, in the untranslated region of the RAD51 gene elevates breast cancer risk among BRCA2 carriers. In this study, it was investigated whether this polymorphism is related to prognosis of breast cancer and RAD51 protein expression and whether it is indicative of resistance to radiotherapy or cyclophosphamide/methotrexate/5-fluorouracil (CMF) chemotherapy.

PATIENTS AND METHODS

We genotyped 306 patients with early breast cancer, who were randomised to receive post-operative radiotherapy or CMF chemotherapy, for the RAD51 135G>C polymorphism. RAD51 protein expression was evaluated with immunohistochemistry.

RESULTS

15.4 % of the patients had at least one C-allele (three were C homozygotes). There was no correlation between genotype and protein expression. Patients who were G homozygotes benefitted from radiotherapy with decreased risk of local recurrences (RR = 0.32, 95 % C.I. 0.16-0.64, p = 0.001). CMF chemotherapy reduced the risk of distant recurrence for patients carrying at least one C-allele (RR = 0.29, 95 % C.I. 0.10-0.88, p = 0.03), whereas G homozygotes had no benefit from chemotherapy. There was a significant interaction between chemotherapy and genotype (p = 0.02).

CONCLUSION

The results suggest that the RAD51 135G>C polymorphism predicts CMF chemotherapy effect in early breast cancer.

Ethnic background and genetic variation in the evaluation of cancer risk: a systematic review

The clinical use of genetic variation in the evaluation of cancer risk is expanding, and thus understanding how determinants of cancer susceptibility identified in one population can be applied to another is of growing importance. However there is considerable debate on the relevance of ethnic background in clinical genetics, reflecting both the significance and complexity of genetic heritage. We address this via a systematic review of reported associations with cancer risk for 82 markers in 68 studies across six different cancer types, comparing association results between ethnic groups and examining linkage disequilibrium between risk alleles and nearby genetic loci. We find that the relevance of ethnic background depends on the question. If asked whether the association of variants with disease risk is conserved across ethnic boundaries, we find that the answer is yes, the majority of markers show insignificant variability in association with cancer risk across ethnic groups. However if the question is whether a significant association between a variant and cancer risk is likely to reproduce, the answer is no, most markers do not validate in an ethnic group other than the discovery cohort's ancestry. This lack of reproducibility is not attributable to studies being inadequately populated due to low allele frequency in other ethnic groups. Instead, differences in local genomic structure between ethnic groups are associated with the strength of association with cancer risk and therefore confound interpretation of the implied physiologic association tracked by the disease allele. This suggest that a biological association for cancer risk alleles may be broadly consistent across ethnic boundaries, but reproduction of a clinical study in another ethnic group is uncommon, in part due to confounding genomic architecture. As clinical studies are increasingly performed globally this has important implications for how cancer risk stratifiers should be studied and employed.

Association between the RAD51 135 G>C polymorphism and risk of cancer: a meta-analysis of 19,068 cases and 22,630 controls

BACKGROUND

RAD51 135G>C can modify promoter activity and the penetrance of BRCA1/2 mutations, which plays vital roles in the etiology of various cancer. To date, previous published data on the association between RAD51 135G>C polymorphism and cancer risk remained controversial. Recent meta-analysis only analyzed RAD51 135G>C polymorphism with breast cancer risk, but the results were also inconsistent.

METHODS

A meta-analysis based on 39 case-control studies was performed to investigate the association between cancer susceptibility and RAD51 135G>C. Odds ratios (OR) with 95% confidence intervals (CIs) were used to assess the association in different inheritance models. Heterogeneity among studies was tested and sensitivity analysis was applied.

RESULTS

Overall, no significant association was found between RAD51 135G>C polymorphism and cancer susceptibility in any genetic model. In further stratified analysis, significantly elevated breast cancer risk was observed in BRCA2 mutation carriers (recessive model: OR = 4.88, 95% CI = 1.10-21.67; additive model: OR = 4.92, 95% CI = 1.11-21.83).

CONCLUSIONS

This meta-analysis suggests that RAD51 variant 135C homozygote is associated with elevated breast cancer risk among BRCA2 mutation carriers. Moreover, our work also points out the importance of new studies for RAD51 135G>C association in acute myeloid leukemia, especially in Caucasians, where at least some of the covariates responsible for heterogeneity could be controlled, to obtain a more conclusive understanding about the function of the RAD51 135G>C polymorphism in cancer development.

Two nonsynonymous polymorphisms (F31I and V57I) of the STK15 gene and breast cancer risk: a meta-analysis based on 5966 cases and 7609 controls

OBJECTIVES

This meta-analysis examined the relationship between two nonsynonymous polymorphisms (F31I and V57I) of the aurora kinase A (STK15) gene and breast cancer risk.

METHODS

A systematic search of the PubMed® and EMBASE™ databases was undertaken to identify case-control studies that investigated the relationship between STK15 gene polymorphisms and breast cancer risk.

RESULTS

This meta-analysis included seven case-control studies (5966 breast cancer cases; 7609 controls). Combined results, based on all seven studies, showed that breast cancer cases had a significantly higher frequency of the 31 Ile/Ile genotype. In a subgroup analysis by race, breast cancer cases had a significantly higher frequency of the 31 Ile/Ile genotype in Asians and Caucasians. Combined results, based on four studies, suggested that the STK15 V57I gene polymorphism was unlikely to be associated with breast cancer risk in either Asians or Caucasians.

CONCLUSIONS

The present meta-analysis suggests that the STK15 F31I polymorphism is a strong predisposing risk factor for breast cancer, but no significant association existed between the STK15 V57I polymorphism and the risk of breast cancer.

Lack of association between the 135G/C RAD51 gene polymorphism and the risk of colorectal cancer among Polish population

One of the major causes of carcinogenesis is loss of genome stability. RAD51 in process of homologous recombination (HR) played crucial role in maintenance integrity of genome through initiate of DNA double strand breaks repair. Presence of single nucleotide polymorphism (SNP) in RAD51 gene could change the capacity of DNA repair and altered the response to damaging agents. Research on potential impact of genetic variability on development and progression CRC may contribute to setting new genetic markers or/and determined individual susceptibility to CRC.The aim of the study. This study was designed to evaluate the effect of 135 G/C (rs1801320) RAD51 polymorphism located in the 5' untraslated region on the risk and progression of CRC.Material and methods. The subjects consisted of histologically confirmed colorectal cancer (n = 200) and controls (n = 200) with lack of previous history of cancer. The distribution of genotypes was determined by restriction fragment length polymorphism PCR (RFLP - PCR). Statistical analysis was based on multivariate regression model.Results and conclusion. Our study reveal no significance association of 135 G/C RAD51 polymorphism with occurrence and progression of colorectal cancer.