Breast cancer risk associated with genes encoding DNA repair MRN complex: a study from Punjab, Pakistan.

BACKGROUND: Variants of DNA repair genes are extensively reported to cause genetic instability and increase the risk of breast cancer. In combination with NBS1, MRE11 and RAD50 constitute an MRN (MRE11-RAD50-NBS1) complex that repairs DNA damage. However, certain genetic alterations in MRE11 and RAD50 produce abnormal protein that affects the repairing process and may result in malignancy. We aimed to investigate the association of MRE11 and RAD50 polymorphisms with breast risk in the female population of Punjab, Pakistan.

METHODS: We collected blood samples of 100 breast cancer patients and 100 tumor-free females selected as controls. Extracted DNA was genotyped by tetra ARMS-PCR followed by gel electrophoresis. Results were analyzed by SPSS and SNPstats to analyze the association of different clinical factors and SNPs (single nucleotide polymorphisms) with the risk of breast cancer.

RESULTS: We found that the increased risk of breast cancer is associated with MRE11 variant rs684507 (odds ratio-OR 3.71, 95% confidence interval-CI 1.68-8.18, p value < 0.0001), whereas, RAD50 variant rs28903089 appeared to have protective effect (OR 0.55, CI 0.29-1.02, p value = 0.003). Additionally, clinical factors such as positive family history, life style, and marital status also play significant roles in breast cancer development.

CONCLUSION: In the present study, strong risk of breast cancer was associated with MRE11 gene. However, RAD50 showed protective effect. Additionally, clinical factors are also pivotal in risk assessment. We anticipate that targeting specific genetic variations confined to ethnic groups would be more effective in future therapeutic approaches for prevention and treatment of breast cancer.