HPGD and lung carcinoma: Studies have revealed that 15-PGDH expression was reduced in colon, breast, gastric and lung cancers and restoration of 15-PGDH could inhibit tumorigenesis in xenografts, indicating that 15-PGDH was a tumor suppressor in these tumors as well as played an essential role in regulating tumor development and progression (16, 17, 18).