Evidence that CHK2 is degraded at the end of the DDR comes from work in the cervical cancer cell line HeLa, where CHK2 levels dropped at just 1 h after irradiation (Schwarz et al., 2003) and in the A2780 ovarian cancer cell line where it was degraded in response to cisplatin treatment (Zhang et al., 2005). This evidence concerns the gene CHEK2 and ovarian carcinoma.