Retrospective cohort studies of CRC cases have identified several key players in the EGFR signalling pathway (which is a signalling network shared by both MAPK and PI3K/PKB pathways) that hinder the effectiveness of anti-EGFR monoclonal antibodies in KRAS wild-type CRC patients (Sartore-Bianchi et al., 2009; Laurent-Puig et al., 2009; De Roock et al., 2010). Here, PIK3CA is linked to colorectal carcinoma.