Cdc25A is an instrumental protein phosphatase in cell cycle progression that is overexpressed in many types of human cancer. However, the role of Cdc25A in cancer metabolism is unclear, and although its role in the regulation of Cdk dephosphorylation is well established, Cdc25A may contain other important cellular substrates. We revealed that EGF stimulation induces PKM2 phosphorylation in the cytosol, which is essential for the nuclear translocation of PKM2. In the nucleus, PKM2 is dephosphorylated by interacting with Cdc25A, which is required for EGF-induced ß-catenin transactivation. We hypothesize that Cdc25A regulates cancer metabolism and tumor progression by dephosphorylating nuclear PKM2. To test this hypothesis, we will pursue three specific aims: (1) To further elucidate the mechanisms underlying Cdc25A-dependent PKM2 dephosphorylation and the subsequent activation of ß-catenin; (2) To determine the role of Cdc25A-dependent PKM2 dephosphorylation in the Warburg effect, tumor cell proliferation, and brain tumorigenesis; and (3) To determine the clinical significance of Cdc25A-dependent PKM2 dephosphorylation in human glioma. The proposed research is significant because it could lead to pharmaceutical approaches to interrupt cancer metabolism by blocking the function of Cdc25A; this would, in turn, improve the efficacy of human cancer treatment.