The dysregulation of several signaling pathways involved in fundamental cellular processes, including cell proliferation, differentiation, angiogenesis, apoptosis, and survival, (e.g., Wnt, TGF-β, MAPK, PI3K/Akt, EGFR, and Notch signaling pathways) are reported as key factors in CRC onset. This evidence concerns the gene PIK3CA and colorectal carcinoma.