PIK3CA and malignant colon neoplasm: Moreover, ERBB2 was recently found to be amplified in a third of tumors, predominantly colon cancer, confirmed to be wild-type for KRAS/BRAF/PIK3CA but resistant to anti-EGFR antibody therapy; tumors with ERBB2 amplification were substantially enriched in this specific population compared to unselected patients [12].