KRAS and fibrosarcoma: It was reported that CRC located in the cecum, ascending colon and two-thirds of the transverse colon (so-called right-sided tumors) have a worse prognosis and is connected with CpG island methylator phenotype (CIMP), microsatellite instability, more frequent mutations of B type rapidly accelerated fibrosarcoma (BRAF) and Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) genes.