PRKAA1 and skin neoplasm: In summary, of the 75 cases of human skin cancer or melanoma where mis-sense mutations in the PRKAA2 gene were recorded and that we successfully expressed in HEK-293 cells (corresponding to 55 separate mutations, since some were listed multiple times), we found that 9 (12%) caused a total loss of AMPK activity, 18 (24%) caused a partial loss of phenformin-stimulated kinase activity, 11 (15%) caused an increase in phenformin-stimulated kinase activity, while 37 (49%) had no obvious effect on kinase activity.