RNAi-based screens were used to identify new targets that, in concert with MEK inhibition, augment the antiproliferative activity of MEK inhibitors in KRAS mutant colorectal cancer cell lines, revealing that c-Raf knockdown, or c-Raf inhibitors, were able to potentiate the activity of MEK inhibitors in KRAS mutant tumor cells (Lito et al., 2012; Lamba et al., 2014). This evidence concerns the gene RAF1 and colorectal cancer.