Moreover, CD31pos/CD26pos proliferative hemangioma–derived endothelial cells (Hem-ECs) were freshly isolated, exposed to vildagliptin (a DPP-IV/CD26 inhibitor), and tested for cell survival and proliferation by MTT assay, FACS analysis, and Western blot assay. The gene discussed is DPP4; the disease is hemangioma.