Indeed, the CRC cell line DLD1 responding to Cetuximab exhibited two PIK3CA exon 9 mutations (p.E545K, p.D549N), PIK3CA exon 20 mutations (p.H1047R) were only observed in CRC cases with progressive disease and short overall survival under EGFR-targeted therapy. This evidence concerns the gene PIK3CA and colorectal carcinoma.