PKM and cancer: In addition to tumor development, PKM2 is involved in regulation of the Warburg effect (Fig. 2) [23], cancer metastasis [24], epithelial mesenchymal transition (EMT) [25–27], gene expression [20], mitosis [28, 29], cellular proliferation [30, 31], apoptosis [32], DNA damage response [33], and exosome secretion [34] (see discussion below).