PTEN and lung cancer: PPARβ/δ activation with ligand GW501516 increases cell proliferation, anchorage-independence of cell growth, and suppresses cell death in lung cancer cell lines by inducing Akt phosphorylation, upregulating of pyruvate dehydrogenase kinase 1 (PDK1), reducing phosphatase and tension homolog (PTEN), and enhancing expression of B-cell lymphoma-extra-large (Bcl-xL) and COX2.