KRAS and carcinoma: The most common subtype, serous carcinoma, can be classified on a molecular basis into two major groups (type I, low-grade carcinomas and type II, high-grade carcinomas) according to p53 (high-grade carcinomas; Ahmed et al, 2010) or KRAS/BRAF (low-grade carcinomas) mutations (Cho and Shih, 2009).