NAV3 and glioblastoma: Interestingly, previous studies showed that GBM cells derived from the tumor core and invasive margin had distinct morphologies, with core cells being rounder compared to the more elongated cells isolated from the tumor edges [44, 47], which would be indicative of the low and high NAV3 levels we detected in our spheroid core/edge samples and consistent with NAV3 levels detected in amoeboid/mesenchymal cells.