Besides the receptor tyrosine kinase/KRAS/BRAF/MEK pathway, other pathways frequently deregulated in colorectal cancers include p53, the TGFβ/SMAD cascade, and the WNT/β-catenin/adenomatous polyposis coli (APC) pathway, which is most commonly activated through mutations in tumor suppressor APC [9]. This evidence concerns the gene KRAS and colorectal cancer.