PKM and hepatocellular carcinoma: In addition, there was lower expression of PKM in liver tissues and hepatocellular carcinomas, probably because of the high proportion of liver and red blood cell type of pyruvate kinase (PKLR, 80.6% in normal liver samples, 46.4% in hepatocellular carcinomas, and less than 1% in most other samples) (S1 Fig).