SLC29A2 and neoplasm: Based on these results, we propose that the secretion of hypoxanthine by highly metastatic cells (MDA-MB-231) and not by the low metastatic cells (MCF-7) contributes to the metastatic behavior in the tumor microenvironment of MDA-MB-231 cells by making the neighboring cells are more susceptible to the effect of hypoxanthine through ENT2 and the induction of EMT effect.