From a molecular point of view, the tumor suppressor genes APC, TP53, PTEN, TGFβ, SMAD4, the oncogenes KRAS, BRAF, HER2, and the tumor-modifying genes COX2, PPAR and CHEK2 play an essential role in the development of CRC [249]. The gene discussed is SMAD4; the disease is colorectal carcinoma.