KRAS and cancer: This notion may be most pertinent to cancers in which RAS alterations are most prevalent (e.g., pancreatic and colorectal carcinomas); although KRAS is only mutated in <1% of high-grade serous ovarian carcinomas, mutations in KRAS or BRAF and other components of the mitogen-activated protein kinase (MAPK) pathway are more prevalent in low-grade serous and also serous borderline forms of ovarian tumors (88–90).