HPGD and colitis: Kim et al. [42] demonstrated that SAV1-knockout or 15-PDGH (hydroxyprostaglandin dehydrogenase 15)-knockout mice did not develop spontaneous tumors after the induction of colitis, but the SAV1/15-PDGH double knockout mice developed polyps which eventually progressed to carcinoma in situ, suggesting a cooperation of the loss of both in cancer development.