The MTHFD1 1958AA homozygous genotype was significantly less frequent among patients affected by colon cancer as compared to cancer-free subjects (17.1% versus 30.9%, p = 0.025) and this difference was confirmed when considering MTHFD1 1958A allele carriership (68.3% in colon cancer versus 83.8% in controls, p = 0.014). The gene discussed is MTHFD1; the disease is malignant colon neoplasm.