ESR1 and PIK3CA Polymorphisms as Potential Genetic Susceptibility Markers for Breast Cancer Risk in Bangladeshi Women: A Case-Control Study.

Breast cancer (BC) is one of the most common and deadly cancers affecting women worldwide. This study is aimed at investigating the association between BC risk and two single nucleotide polymorphisms (SNPs): ESR1 (rs2234693) and PIK3CA (rs6443624) in a Bangladeshi population. A case-control study was conducted with 112 BC patients and 124 healthy controls (HCs). Genomic DNA was extracted from peripheral blood samples, and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genotype and allele frequencies were analyzed to assess their association with BC risk. Genotype distributions for both ESR1 and PIK3CA conformed to Hardy-Weinberg equilibrium. The CT genotype of ESR1 was associated with a reduced risk of BC, whereas the CA genotype of PIK3CA was linked to an increased risk. The dominant model for ESR1 (CT + TT vs. CC) demonstrated a significant protective effect (aOR = 0.288, 95% CI: 0.160-0.516), whereas the dominant model for PIK3CA (CA + CC vs. AA) showed a higher risk (aOR = 4.166, 95% CI: 2.363-7.347). Over-dominant models supported these findings, while recessive models for both SNPs showed no significant associations. The findings suggest that ESR1 (rs2234693) may have a protective role and PIK3CA (rs6443624) may increase susceptibility to BC in Bangladeshi women. These SNPs may provide preliminary evidence for potential use as genetic susceptibility markers, but larger multicenter studies are needed before any clinical application can be considered.