CDKN2A and astrocytoma (excluding glioblastoma): At 12 weeks highly invasive GFAP-/Nestin + high-grade astrocytomas develop, a progression that is accompanied by additional changes including overexpression of EGR, MDMT, loss of Pten and p16 and p19 [50], all of which are known genetic markers associated with malignant human gliomas.