Combining a MEK1/2 inhibitor with ABT‐263 is also effective in vivo, including in xenograft models of the KRAS‐mutant colorectal cancer cell lines (HCT116, SW620, SW1463) and a genetically engineered KRAS‐driven lung cancer mouse model where the combination caused 70–80% tumour regression 86. Here, MAP2K1 is linked to colorectal cancer.