Immunoblot analysis of common pathway aberrations in these subclasses (Brennan et al, 2009) and other subclass markers (Phillips et al, 2006) revealed clustering of ZEB1 in the proliferative subclass, while ZEB1 negative tumours were slightly enriched for mesenchymal and proneural subclasses (Fig 6E). This evidence concerns the gene ZEB1 and neoplasm.