NRAS and colorectal carcinoma: Current guideline for anti-EGFR therapy relies on negative predictive biomarkers that select patients without activating mutations in KRAS and NRAS. Efforts have been made to identify resistance mechanisms to anti-EGFR therapy such as BRAF mutation, HER2 amplification, and c-MET amplification by means of NGS in metastatic CRC [14, 15].