The STAMPEDE (Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy) trial is investigating whether addition of metformin has beneficial effects in men with high-risk locally advanced or metastatic PCa.44 However, as far as we are aware, it is not known whether metformin leads to activation of AMPK in the prostate, and so other approaches may need to be considered. This evidence concerns the gene PRKAA1 and Familial prostate cancer.