PTEN and colorectal carcinoma: Several retrospective analyses confirmed that patients with CRC harboring mutations of Kirsten rat sarcoma viral oncogene homolog (KRAS), Neuroblastoma RAS viral oncogene homolog (NRAS), v-Raf murine sarcoma viral oncogene homolog B (BRAF) or phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), or loss of the phosphatase and tensin homolog (PTEN), a negative regulator of the PI3K/AKT pathway, associate with reduced response rates to anti-EGFR antibodies [9, 15–25].