Methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphisms in breast cancer: A Filipino preliminary case-control study

Abstract

Single nucleotide polymorphisms (SNP) present in folate metabolic enzymes, such as methylenetetrahydrofolate reductase (MTHFR), affect DNA synthesis and methylation processes that can lead to cancer development. Several studies suggest that MTHFR SNP is associated with breast cancer risk, particularly among Asian populations. Thus, this study determined the association of MTHFR 677C>T SNP with breast cancer risk in selected Filipino population. DNA samples from breast cancer cases (n = 100) and clinically healthy controls (n = 100) were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The differences in MTHFR genotype and allele frequencies were evaluated by computing for the odds ratio (OR) with a 95 % confidence interval (CI). The CT genotype (OR: 0.775, 95 % CI: 0.35–1.71, p = 0.53), T allele (OR: 0.703, 95 % CI: 0.34–1.48, p = 0.35), and presence of at least one T allele (ORCT+TT: 0.729, 95 % CI: 0.33–1.60, p = 0.43) were not associated with breast cancer risk. Based on the SNP interaction with other risk factors, no significant difference (p > 0.05) was observed for the tumor characteristics, menarche age, and menopause age. Interestingly, a decreased risk (OR: 0.342, 95 % CI: 0.14–0.84, p = 0.019) was observed for the CC genotype in individuals who consumed dietary fibers. Meanwhile, there was an increased risk for passive smokers with the CC genotype (OR: 6.31, 95 % CI: 2.68–14.9, p < 0.001). Overall, the MTHFR 677C>T was not significantly associated with breast cancer risk in a selected Filipino population. Since this study involved a relatively small number of participants, increasing the number of samples is recommended for a more conclusive test of association of MTHFR 677C>T with breast cancer risk in Filipinos.