When hypoxia occurs, the transcription factor HIF-1α is activated and induces the expression genes involving in glycolysis, including glucose transporter 1 (GLUT1), glucose transporter 3, hexokinase 2, pyruvate kinase 2, lactate dehydrogenase 5, and pyruvate dehydrogenase kinase 1 (PDK1).116 Therefore, HIF-1α serves as a key molecule for the anticancer drugs targeting cancer metabolism. Here, PDK1 is linked to cancer.