The investigation on the potential links between the HDAC family and the pathological grade, and the genetic alterations of glioma, revealed that the expression levels of HDAC1, HDAC2, and HDAC11 significantly altered with the glioma grade (HDAC1, p = 1.25e−13; HDAC2, p = 0.0025; HDAC11, p = 3.74e−12) and the IDH1 mutation status (HDAC1, p = 5.5e−16; HDAC2, p = 0.0098; HDAC11, p = 9.53e−05) (Figures 3A,D; Figures 4A,C; Table 2). The gene discussed is HDAC9; the disease is glioma.