TGFB1 and cancer: We have previously reported that TGF-β isoforms increase XIAP protein levels in endometrial carcinoma cells [6] and we observed that each TGF-β isoform also upregulates XIAP protein content in HeLa cervical carcinoma cells (Figure 2A), indicating that the regulation of XIAP protein levels by TGF-β is not restricted to cancer cells from the endometrium.