RPS6KB1 and Familial prostate cancer: The antitumor effects of metformin on breast and prostate cancer cells have been demonstrated in in vivo and in vitro experiments, since rapamycin/ribosomal protein S6 kinase beta-1 (mTOR/S6K1) activity is suppressed by adenosine monophosphate-activated protein kinase (AMPK) activation [43,44].