Numerous molecular genetic studies of CRC have revealed many genes that are characterized by high frequency of mutations (KRAS, NRAS, BRAF, PIK3CA, APC, TP53, SMAD2, SMAD4, ARID1A, SOX9, FAM123B/WTX, and FBXW7), copy number alterations (ERBB2 and IGF2), methylation status changes (MLH1), impaired expression at the mRNA or protein level, and translocations (NAV2/TCF7L1) [2, 3]. The gene discussed is SMAD4; the disease is colorectal carcinoma.