Abstract
OBJECTIVES: Breast cancer is one of the most common malignancies in women. The PD1 and MTNR1B gene polymorphisms have been extensively studied for their potential role in cancer susceptibility. This study aimed to investigate associations between breast cancer risk and PD1 (rs36084323) and MTNR1B (rs10830963) polymorphisms. METHODS: A case-control study was conducted with 112 breast cancer patients from Dhaka Cancer and General Hospital, Bangladesh, and 124 age- and sex-matched healthy controls. Genotyping of PD1 (rs36084323) and MTNR1B (rs10830963) polymorphisms was performed using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. RESULTS: The genotype distributions for both SNPs adhered to Hardy-Weinberg equilibrium (HWE). The PD1 GG genotype was more prevalent in controls, indicating a protective effect, whereas the GG genotype of MTNR1B showed no statistically significant association with breast cancer risk. The recessive model of PD1 (GG vs. AG + AA) demonstrated a lower odds ratio (0.2873), while the recessive model of MTNR1B (2.307) suggested a potential risk. Dominant models for both genes (AG + GG vs. AA for PD1 and CG + GG vs. CC for MTNR1B) showed statistically significant associations with breast cancer susceptibility. CONCLUSION: The PD1 GG genotype exhibited a significant protective effect against breast cancer, while the MTNR1B CG genotype was associated with reduced risk, but GG showed no correlation. Larger studies across diverse populations are recommended to validate these findings.