This research also conducted in vivo experiments using PDX derived from a patient with CRC carrying four wild-type genes [without mutations, BRAF, KRAS, NRAS (genes of signaling proteins, members of the RAS family), and PIK3CA (encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K))], which replicated the gene expression profile of patients sensitive to anti-EGFR antibodies. Here, PIK3CA is linked to colorectal carcinoma.