The human genes SMC1, SMC3, NIPBL, STAG3, RNF20, FBXW7/CDC4, MRE11A, RAD54B and BLM have been found to be mutated in colorectal cancer, and together account for approximately 25% of the CIN mutational spectrum of this disease [13]–[15], [20]–[22]. Here, STAG3 is linked to colorectal cancer.