Previous studies have demonstrated that MEK inhibition stimulates AKT activity through an ERK-mediated feedback loop activation.37–39 Since colon cancer cells treated with IGF-1R inhibitors do not change the ERK phosphorylation (Fig. 6a and ref. 27), ERK does not likely play a role in AKT activation. This evidence concerns the gene MAP2K7 and malignant colon neoplasm.