ARF6 and neoplasm: Under physiological condition, Arf6 and AMAP1 proteins are both highly expressed in vesicular endothelial cells upon vesicular endothelial growth factor (VEGF) stimulation; and the GEP100-Arf6-AMAP1 pathway is crucial for VEGF-, as well as tumor-induced angiogenesis in vivo and in vitro [25].