The fact that both lower grade gliomas and GBMs display similar rates of LOH of ZEB1 despite the chromosomal loss in GBMs but not in lower grade gliomas suggests the independent occurrence of LOH at ZEB1. Furthermore, the prognostic significance of ZEB1 loss in both lower grade gliomas and glioblastomas may suggest that, lower grade gliomas that lose ZEB1 ultimately progress to GBMs, where the continued loss of ZEB1 progressively impacts overall prognosis. This evidence concerns the gene ZEB1 and central nervous system cancer.