XIAP and chondrosarcoma: DNA damage or other events that result in induction of apoptosis can lead to ubiquitination and autoubiquitination of XIAP.17 However, activation of BMPR2 can stabilize XIAP via preventing ubiquitination and subsequent degradation.18 As shown in Figure 4c, in chondrosarcoma cells, silencing BMPR2 by siRNAs led to significantly decreased expression of XIAP.