To accomplish this, c-Myc induces expression of key glycolytic enzymes; it also increases the ratio of pyruvate kinase M2 (PK-M2) to pyruvate kinase M1 (PK-M1) by indirectly modulating exon splicing, thereby enforcing a shift toward lactic acid production, a prominent marker of cancer progression (75). This evidence concerns the gene MYC and cancer.