NRAS and colorectal carcinoma: Sveen et al. (2012) proposed a prognostic model by studying gene expression in tumor tissues, which has potential prognostic value in stage IV and V CRC patients. In addition, a large number of genes, including P53 (Lüchtenborg et al., 2004), K-ras (Andreyev et al., 1990), B-raf (De Roock et al., 2010), and N-ras (Parsons et al., 2012), have been shown to be associated with the prognosis of CRC.