A number of MEK1/2 inhibitors are currently being investigated in the clinic across a range of cancers [16–19] including gynecologic malignancies [20], melanoma [17, 21], colorectal cancer [17], and acute myelogenous leukemia [22], with trametinib approved alone and in combination with the BRAF inhibitor dabrafenib for advanced metastatic melanoma with BRAF V600 mutations [23]. Here, BRAF is linked to acute myeloid leukemia.