KRAS and colorectal carcinoma: According to genetic pathways involved, CRC follow the chromosomal instability (CIN) pathway with loss of heterozygosity (LOH) of tumor suppressor genes (such as adenomatous polyposis coli (APC) and tumor protein 53 (TP53)) and activation of proto-oncogenes (such as V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS)) or the microsatellite instability (MSI) pathway with frequent aberrations in the DNA mismatch repair (MMR) machinery [93].