PIK3CA and colorectal carcinoma: This led, apart from the identification of FGFR1, ERBB2, NRG, GNAS, and MET amplifications, to the discovery of emerging KRAS, NRAS, PIK3CA, BRAF, EGFR, and IRS1 mutations in resistant CRC subpopulations mediating SR towards anti-EGFR therapy [4, 6, 7, 12, 13, 15–18].