Spheroid volume increase of NSC and UW228-3 cells as a function of initial seeding number.

Volume increase % = 100*(Vday7−Vday1)/Vday1. NSCs grew more in a week than UW cells, reaching maximum growth increase of 600% for seeding 1000 cells per spheroid, whereas the maximum growth increase for tumour cells was around 170% for 2000–5000 cells/spheroid.