NRAS and colorectal carcinoma: In colorectal cancer (CRC), activating mutations in KRAS (codons 12, 13, 61, 117 and 146), NRAS (codons 12, 13, 61, 117 and 146), and BRAF (V600E) confer resistance to anti-epidermal growth factor receptor (EGFR) therapy including Cetuximab and Panitumumab1–4.