Polymorphisms in methylenetetrahydrofolate reductase and cystathionine beta-synthase in oral cancer - a case-control study in southeastern Brazilians.

INTRODUCTION Oral squamous cell carcinoma (OSCC) is a serious public health problem, due to its high mortality rate and worldwide rising incidence. OSCC susceptibility is mediated by interactions between genetic and environmental factors. Studies suggest that genetic variants encoding enzymes involved in folate metabolism may modulate OSCC risk by altering DNA synthesis/repair and methylation process. OBJECTIVE The goals of this study were to evaluate the association of three genotypic polymorphism (MTHFR C677T, MTHFR A1298C and CBS 844ins68) and oral cancer risk in southeastern Brazilians and evaluate the interactions between polymorphisms and clinical histopathological parameters. METHODS This case-control study included 101 cases and 102 controls in the state of Espírito Santo, Brazil. MTHFR genotyping was done by PCR-RFLP (polymerase chain reaction - restriction fragment length polymorphism) and CBS genotyping by PCR (polymerase chain reaction) analysis. RESULTS MTHFR C677T polymorphism was associated with lymph node involvement. Genotype CT+TT acted as a protective factor. MTHFR A1298C AC+CC genotype was associated with tumor differentiation, and possibly with a better prognosis. In risk analysis, no correlation was observed between genotypes and OSCC. CONCLUSION We concluded that MTHFR C677T, MTHFR A1298C and CBS 844ins68 polymorphisms were not associated with OSCC risk in southeastern Brazilians; however, we suggest a prognosis effect associated with MTHFR C677T and A1298C polymorphisms in OSCC.