MAP2K1 and malignant colon neoplasm: In contrast, overexpression of an active form of MEK1 had only a minimal effect on inhibition of cell viability mediated by miR-497 mimics (Figure 4d), suggesting that the moderate inhibition of the MEK/ERK pathway does not have a major role in reduced cell viability when miR-497 is overexpressed in colon cancer cells.