Besides, Dong et al. reported that the PDE inhibitor of PDE3, PDE4, PDE7 and PDE8 impaired the migration of aggressive triple negative MDA-MB-231 breast cancer cells but had little effect on breast cancer cell proliferation [24], which implicated the inconsistence between PDE activity and anti-tumor effects in different cancer. The gene discussed is ALDH7A1; the disease is neoplasm.