PRKAA1 and neoplasm: Mannose, a C-2 epimer of glucose,18 is not only an effective nonantibiotic drug for urinary tract infections,19 but also a potential agent for impairing tumor growth upon combination with conventional chemotherapy.20 We found that the metabolism of mannose in the cells elevated the level of the metabolite N-acetylglucosamine-6-phosphate (GlcNAc-6P), which bound and activated AMPK.