Decreased (hydroxyprostaglandin dehydrogenase 15 (15-PGDH, HPGD) mRNA expression in tumor samples relative to that of normal samples was obvious (Fig. 1d), whereas prostaglandin-endoperoxide synthase 2 (COX-2, PTGS2) mRNA failed to present a difference between tumor and normal samples (Fig. 1e). The gene discussed is PTGS2; the disease is neoplasm.