It should be noted that the CT26 colorectal cancer model is p53-proficient but carries - as HCT116 cells do - an activating mutation in kirsten rat sarcoma viral oncogene homologue (KRAS), an oncogene which is of pivotal importance in colorectal cancer, as mutations have been reported in approximately 50% of all cases [69]. This evidence concerns the gene TP53 and colorectal cancer.