Association of MTHFR 677C>T polymorphism with breast cancer risk: A case-control study and meta-analysis

Breast cancer is a complex, multifactorial disease that arises as a result of interactions between multiple genes and environmental factors. Methylenetetrahydrofolate reductase (MTHFR) is a low susceptibility gene, involved in folate metabolism. It assists in conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate which further leads to DNA methylation. 5,10-methylenetetrahydrofolate assists in conversion of uracil to thymine and purine synthesis for DNA synthesis. MTHFR 677C>T polymorphism alters the activity of MTHFR enzyme potentially effecting DNA repair and synthesis, hence a potential risk for cancer like breast cancer. Hence, the present study was conducted to evaluate association of MTHFR 677C>T polymorphism and breast cancer in Punjabi population. Moreover, a meta-analysis was conducted to address the same.

A total of 247 breast cancer patients and 247 controls were selected from Punjabi population for analysis using PCR-RFLP method. For meta-analysis, 67 studies were selected, and allele contrast, homozygous, heterozygous, dominant, and recessive models were used to evaluate the association between MTHFR 677C>T and breast cancer.

The frequencies of CC, CT, and TT genotype were 68.4% versus 74.5%, 28.7% versus 23.5%, and 2.9% versus 2.0% in patients and controls, respectively. There was no significant difference found. In meta-analysis, significant association was found in overall and Asian population while no significant association was found in Caucasians.

MTHFR 677C>T polymorphism is not a risk factor for breast cancer in Punjabi population. Inconsistency with the meta-analysis can be due to ethnic diversity.