HDAC9 and glioma: In summary, HDAC and co-factors gene expression levels discriminate subgroups ofpatients that do not necessarily belong to the same histopathologic grade(e.g. some ODIII cluster with GL tumors, Figure2A) and even within the same grade, molecular subgroups wereidentifiable, which challenges the histopathological classification and mightexplain why all glioma patients do not respond equally to the availabletherapeutic protocols.