  In this paper we analyse a differential system related to a Glioblastoma
growth. Using numerical simulations, we prove that model captures different
kind of growth changing adequately the parameters of the model. Firstly, we
make an adimensional study in order to reduce the number of parameters. Later,
we detect the main parameters determining either different width of the ring
formed by proliferative cells around necrotic ones or different
regular/irregular behaviour of the tumor surface.
