Univariate Cox regression indicated that high expression levels of HDAC1, HDAC3, HDAC7 and HDAC9 were associated with poor OS of glioma, and elevated expression levels of HDAC4, HDAC5, HDAC6 and HDAC11 were associated with a favorable prognosis of glioma (Figure 2A). The gene discussed is HDAC9; the disease is glioma.