CCL18 and Kaposi's sarcoma: As one of classic materials studied for many years in neovascularization, HUVECs had been surveyed in many tumors before; Bais C found VEGF receptor-2 modulated the trafficing of Kaposi's sarcoma to HUVECs [27], and Lin L found CCL18 exposure activated ERK and Akt/GSK-3β/Snail signaling in HUVECs then promoted angiogenesis in breast cancer [28].