NRAS and malignant colon neoplasm: In one study of 158 patients with metastatic colon cancers and 64 patients with metastatic rectal cancers, colon cancers had a higher BRAF mutation rate compared to rectal cancers (13.3% vs. 3.1%, P < 0.05), but lower rates of NRAS (0.6% vs. 12.5%, P < 0.05) and TP53 mutations (17.7% vs. 29.7%, P < 0.05).