KRAS and neoplasm: CMS1 group (MSI immune subtype, including 14% of all CRCs) is characterized at genetic level by hypermutation, hypermethylation, enrichment for BRAFV600E mutations (observed in 40% of these tumors) and by pronounced infiltration of the tumor microevironment by immune cells, particularly represented by T lymphocytes (both Cytotoxic CD8+ and CD4+ T helper) and natural killer lymphocytes; frequent in these tumors are mutations at the level of APC (35%), TP53 (30%) and KRAS (25%) genes.