Taken together, our results show that iHDAC treatment leads to tunneling tube formation and tumor malignance downgrade in vitro. Our interpretation relies on the fact that iHDAC-treated cells decrease the velocity of migration and downregulate vimentin and connexin 43 expression, and to test whether TSA-treated U87-MG cells in fact harbor the competence to properly respond to environmental cues and downregulate their malignant behavior, we used GBM oncospheres xenografted in the developing neural tube of the chick embryo. Here, VIM is linked to neoplasm.