While the traditional serrated adenoma-induced colorectal carcinoma usually has a low microsatellite instability (MSI-L) and its mechanism of carcinogenesis is mainly K-ras mutation-induced methylation of the MGMT DNA repair gene and a low level of CpG island methylation, which is known as the traditional serrated pathway (1,21). The gene discussed is KRAS; the disease is colorectal carcinoma.