MARK2 and neoplasm: In tumor cells, LDH is translationally upregulated by hypoxia inducible factor (HIF) as well as myc and is thus regulated by the phosphatidylinositol 3-kinase (PI3K)/serine/threonine kinases AKT/mammalian target of rapamycin (mTOR)/HIF pathway or myc overexpression [9, 19–21].