XIAP and breast cancer: In addition to numerous studies elucidating the mechanisms of anti-apoptotic function of XIAP, our recent studies have revealed several non-apoptosis-related functions of XIAP, such as upregulation of Cyclin D1 to promote BC cell growth [6] and colon cancer cell invasion via inhibition of RhoGDIα SUMOylation at lys-138 [7].