BRAF and malignant colon neoplasm: Given that gene mutations (KRAS, BRAF and PIK3CA) influence cetuximab sensitivity, we chose two cell lines (Caco-2 and DiFi) that express wild-type KRAS, BRAF and PIK3CA, paralleling the molecular features of colon cancer patients who are most likely to respond to cetuximab (Supplementary Table S1).