PDHA1 and digestive system cancer: It is remarkable how MPC1 and MPC2, PDHA1 and PC—genes that are involved in the transport and conversion of pyruvate in the inner mitochondrial matrix, respectively—are all significantly downregulated in a subset of colon adenocarcinomas categorized as colon mucinous adenocarcinomas, as loss of these genes essentially shuts down oxidative phosphorylation in the mitochondria (Figure 6—figure supplement 1).