On the other hand, over-expression of either human TFPIβ (TFPI) or a mouse TFPIβ (mTFPI), but not TFPI2, elevated the sensitivity to TcdB4.2 in HeLa cells, and in a human bladder carcinoma cell line 5637 (a cell line that we found to be not sensitive to TcdB4.2) (Fig. 2g–i and Supplementary Fig. 6b). Here, TFPI2 is linked to urinary bladder carcinoma.