PKM and melanoma: Similarly, melanoma derived from co‐injection of replicative senescent fibroblasts with A375 melanoma cells into SCID mice is larger and reveals a consistent overexpression of activated CREB and glycolytic enzymes, including Hexokinase 1, Lactate Dehydrogenase A (LDHA), Pyruvate Kinase isoenzyme M2 (PKM2), while depicting reduced expression of Glutamate Dehydrogenase (GDH), a key enzyme of the TCA cycle.