HDAC9 and neoplasm: A study by Halsall et al. showed that HDAC inhibition increases H3K27me3 in non-H3K27M expressing tumors of human lymphoblastoid cell lines, derived from B-lymphocytes immortalized by Epstein Barr Virus [77], and PRC2 restored its activity in H3K27M tumor poly-acetylated H3 tails [78].