NRAS and rectal cancer: The results showed that KRAS mutations were detected in 44.2% colon cancer, 37.1% rectal cancer and none in gastric cancer; NRAS mutations were detected in 1.2% colon cancer, 4.3% rectal cancer and none in gastric cancer; BRAF mutations were detected in 3.5% colon cancer, 0.7% rectal cancer, and 2.9% in gastric cancer.