PIK3CA and colorectal carcinoma: EGFR inhibition provides additional activity by suppressing the activation of MAPK and other effector pathways, both those engaged directly by EGFR and downstream of Ras, such as PI3K/Akt.59 However, as revealed by both our analyses and clinical experience in CRC,60 multiple cell surface receptors are capable of filling the role of RTK2 and functionally substituting for EGFR, notably MET and the FGFR-family.