CTSB and endometrial cancer: We finally aimed to test whether also E2-BSA- mediated Ca2+ controls lysosomal activity in endometrial cancer cells, the result was verified by Western blot, Cathepsin B (CTSB) was expressed in the lysosomal fraction of Ishikawa cells, E2-BSA treatment caused the CTSB to enter the cytoplasm (Figure 5G).