Their downregulation was significantly higher in Grade IV GBM in comparison with Grade II gliomas (TET1 and TET3 p < 0.001, TET2 p < 0.01) and Grade III gliomas (TET1 p < 0.001, TET2 and TET3 p < 0.01). The gene discussed is TET1; the disease is central nervous system cancer.