KRAS and colorectal carcinoma: In 2014, four consensus molecular subtypes (CMSs) of CRC were developed based on genetic alterations affecting the colonic epithelium: CMS1—microsatellite instability (MSI)-immune (CpG island methylation phenotype, and BRAF mutation associated with immune cell infiltrates); CMS2—canonical (WNT- and MAPK-associated); CMS3—metabolic (KRAS-associated); and CMS4—mesenchymal [3,4].