PROM1 and lymphangioma: CD133− cells isolated from fluids collected from 15 LM patients (cervicofacial LMs (n = 4), mesenteric LMs (n = 4), thoracic LM (n = 1), subcutaneous LMs (n = 4) and GLA (n = 2)) were compared to CD133+ LM cells and neonatal human dermal lymphatic endothelial cells (HdLEC; n = 3).