Previous studies consider HDAC1, –3 and –7 as tumour biomarkers [41] and knockdown of HDAC1, –2, –3 and –6 in a variety of cancer cell lines can promote apoptosis and cell cycle arrest while HDAC1, –2 and -4 are required to maintain cancer cell survival in vivo [42]. The gene discussed is HDAC1; the disease is neoplasm.