Because deregulation of Class I HDAC (HDAC1, 2, 3 and 8) activity from HDACs (of the 18 isoforms) has been associated with cancer (de Ruijter et al., 2003; Weichert, 2009; Müller et al., 2013; Shouksmith et al., 2019) and its involvement has been suggested (Senese et al., 2007) to be crucial in controlling mammalian cell proliferation. Here, HDAC1 is linked to cancer.