HDAC9 and prostate cancer: Consistent with a previous finding that class I HDAC members (HDAC1, 2, 3, and 8) are highly expressed in prostate cancers (Weichert et al, 2008), analysis of TCGA data also showed that expression of these four HDAC genes was upregulated at the mRNA level in tumors compared to normal tissues (Fig EV1A).