MTHFR C677T polymorphism and anatomopathological characteristics with prognostic significance in sporadic colorectal cancer

Methylenetetrahydrofolate reductase (MTHFR) plays a key role in folate metabolism, and folate is implicated in carcinogenesis due to its role in DNA methylation, repair and synthesis. The MTHFR C677T polymorphism is associated with decreased risk of CRC and increased sensitivity to 5-FU treatment. The present study addressed the relationship between this polymorphism and histopathological and immunohistochemical characteristics of prognostic significance in 50 patients from the Canary Islands. No differences were found between the MTHFR C677T genotypes with respect to tumor budding, tumor necrosis, desmoplastic fibrosis and tumoral eosinophilia. No significant differences were found in Ki-67, bcl-2 (cytoplasmic and nuclear), CD31, CD3+ T lymphocytes (both stromal and intraepithelial) and peritumoral CD20+ B lymphocytes. In carriers of the MTHFR CC variant, tumor margins were infiltrative more frequently (68.7%) than in CT + TT carriers (33.3%, p = 0.03). In addition, wild-type CC genotype showed stromal CD20+ B lymphocytes (68.8%) more often than CT + TT carriers (33.3%, p = 0.03). Both parameters indicate a better tumor prognosis when the MTHFR 677T variant is present.