DCN and neuroblastoma: Ultrastructural imaging of the neurospheres revealed both electron-dense and electron-lucent cells, which implies the presence of cells at different stages of differentiation, with peripheral cells enriched in endocytic vesicles, probably for vesicle-mediated internalization of DCN by RTK [66], and cell-specific signs of differentiation, particularly dense granules in NB cells and thin membrane extroflections in GBM cells.