Our observation of the decreased tumor vasculature in A549shHTATIP2 tumors with upregulated HIF2α expression was discordant with an early in vitro study showing that the proliferation and migration of human umbilical vein endothelium cells (HUVECs), human lung microvascular endothelial cells (HLMVECs) and vascular smooth muscle cells (VSMCs) were inhibited when those cells were treated with the culture media conditioned by HTATIP2-expressing small cell lung carcinoma (SCLC) cells [43]. Here, EPAS1 is linked to neoplasm.