CHEK2 and neoplasm: Of interest, the four protein kinases that show negative regulation of SIAH2 (activity and/or stability), namely HIPK2, DYRK2, CHK2, and PLK3, are all considered to have tumor suppressive functions and with roles in the DNA damage response (Gwack et al., 2006; Sombroek and Hofmann, 2009; Li et al., 2017).