PKM and colorectal cancer: In their most cited article, the authors described that miR-124 induced the expression of the pyruvate kinase M (PKM) isoform to catalyze the conversion of PKM2 to PKM1, thereby altering glycolytic metabolism and suppressing human colorectal cancer tumors through a feedback cascade involving polypyrimidine tract-binding protein 1 (PTB1), PKM1, and PKM2 (29).