AQP1 and hemangioendothelioma: The presence of VEGF in normoxic or hypoxic conditions in human retinal vascular endothelial cells does not appear to have any direct effect on AQP1 expression [37]; however, Echevarría et al. reported increased VEGF mRNA expression with siRNA-modulated knockdown of AQP1 in a non-metastatic murine hemangioendothelioma cell line, comparable in vitro with microvascular endothelial cells [38], which is consistent with the results from NCI-H28 cells.