A retrospective observational study of clinicopathological features of KRAS, NRAS, BRAF and PIK3CA mutations in Japanese patients with metastatic colorectal cancer

The mutation in KRAS exon 2 is a validated biomarker of resistance to anti-epidermal growth factor receptor (EGFR) therapy in metastatic colorectal cancer (mCRC). Several reports have confirmed associations of other RAS mutations with resistance to anti-EGFR therapy. However, the impact of BRAF and PIK3CA mutations on the efficacy of anti-EGFR therapy remains controversial.