VEGFA and nasopharyngeal carcinoma: The possible mechanism underlying ANG-promoted radio-resistance in NPC cells is as follows: Since microvesicles derived from mesenchymal stem cells are known to promote angiogenesis, Chen et al. (2014) used an antibody array and found that Angiogenin, VEGF, IGF, Tie-2/TEK, and IL-6 which were higher in microvesicles under hypoxic conditions than under normoxic conditions, which revealed that ANG might be responsible for the hypoxia-augmented proangiogenic effects of microvesicles.