PIK3CA and acute myeloid leukemia: In addition, a signature of eEF2K activity (as measured by its autophosphorylation and phosphorylation of its substrate eEF2) was found to be associated with sensitivity to cotreatment in cell models of acute myeloid leukemia (AML) and could thus represent a biomarker signature to predict synergistic response to cotreatments with MEK and PI3K inhibitors.