PROM1 and adenoid cystic carcinoma: The tumor-activating effect of the CD133-positive endothelial progenitors may also explain communications stating that the VEGF-stimulated CD133-positive cancer cells induce the relapse of the hepatocellular carcinoma [185] or the migration/invasion of salivary adenoid cystic carcinoma cells [165] by inducing the vasculogenic mimicry formation.