RAF1 and colorectal carcinoma: These results are inconsistent with previous results in NSCLC or CRC.15,30 This may be because class 1 BRAF variants (BRAF V600E variants) are RAS-independent, signal as monomers, and are sensitive to current RAF monomer inhibitors, whereas non-V600E BRAF variants, especially class 3 BRAF variants, have low or absent kinase activity and are RAS-dependent and sensitive to ERK-dependent feedback of RAS.