It has been suggested by previous research that increased PPP flux in tumor cells serves as a line of distinction for normal cells [9,10], which is followed by overexpression of PPP enzymes (G6PD and 6-PGD, the first and third enzymes that link glycolysis to PPP by anabolic biosynthesis and NADPH production to maintain redox homeostasis in mammalian cells) in several tumors; therefore, PPP enzymes have been characterized as potential targets for cancer treatment and diagnosis recently. The gene discussed is PGD; the disease is cancer.