MTHFR and cancer: The aim of our study was to investigate the frequency of factor V Leiden (G1691A), factor II Prothrombin (G2021A), MTHFR C677T, MTHFR A1298, and combined polymorphisms in a Greek population by using real-time polymerase chain reaction methods and their possible association with family history of cancer and cardiovascular diseases (CVDs), as well as environmental epigenetic factors that might influence genotype expression.