NRAS mutation is found in several cancers such as melanoma (13~25%), colorectal cancer (1~6%), lung cancer (1%), thyroid cancer (7%) and hepatocellular carcinoma (10%). It is know that the drug response against colorectal cancer medicine such as Erbitux and Cetuximab decreased and the prognosis of the metastatic colorectal cancer patient is bad if the patient has NRAS mutation.