MAP2K1 and breast cancer: Interestingly, there was a modest positive correlation between resistance to AKT inhibition (GDC-0068) and MPAS in breast cancer, supporting reports that, in certain subsets of this disease, the MAPK signaling pathway may mediate resistance to AKT inhibition.27 Of note, hierarchical clustering separated the cancer indications into two classes: those in which MPAS predicted MEK1/2 inhibitor sensitivity (breast, lung, and colorectal), and those in which it did not (pancreatic and melanoma).