Oncogene or Tumor Suppressor: The Coordinative Role of Lysine Methyltransferase SET7/9 in Cancer Development and the Related Mechanisms

SET7/9 is a member of the protein lysine methyltransferase family that methylates both histone 3 lysine 4 (H3-K4) and lysine(s) of other non-histone proteins. In recent years, dis-regulation of SET7/9 were frequently detected in various cancer types and SET7/9-mediated methylation has been recognized as an important mechanism that affects cancer initiation and development through regulation of a series of cellular processes. Here we review the currently identified histone and non-histone protein targets of SET7/9 that are closely correlated with human cancer and the function of SET7/9 in regulating the expression and stability of its protein targets. The review also discusses the putative role of SET7/9 as an oncogene or tumor suppressor in the development of various cancer types and the underlying mechanisms, which may help better evaluate the potential of SET7/9 as a novel candidate for cancer therapy.