IKKε-induced phosphorylation at Ser418 of CYLD decreased its activity (Figure 3C) and completely blocked CYLD-mediated deubiquitination of TRAF2, thereby promoting tumorigenesis in breast cancer cells (Hutti et al., 2009; Massoumi, 2011; Eguether et al., 2014). Here, TRAF2 is linked to breast cancer.