PARP1 and cancer: Support for the hypothesis of dysregulated lactate metabolism in carcinogenesis (3, 9, 168) is found in the results of recent experiments showing that lactate secreted from cancer cells into the stroma surrounding tumors downregulates p62 transcription in stromal cells through a mechanism involving redox change (i.e., the NAD+/NADH ratio, vide supra), which impairs poly(ADP-ribose)-polymerase 1 (PARP-1) activity.