Transitional cell carcinoma expresses high levels of Fas ligand in vivo

Objective To characterize the Fas-Fas ligand system. a main apoptotic pathw ay, in transitional cell carcinoma (TCC) of the urinary bladder, by analysi ng the expression of Fas and Fas ligand (FasL) in TCC samples, Materials and methods Archival paraffin-embedded tissues from 37 patients w ith TCC were analysed by immunohistochemistry to determine Fas and FasL exp ression. Results Fas and FasL were detected on the cell surface and cytoplasm of res pectively 34 (91%) and all cases analysed. The expression of Fas and FasL d id not differ with the cytological grade of TCC. Conclusion The high expression of FasL in TCC, reported for the first lime in the present study, suggests that FasL may contribute to the immune escap e of TCC through killing Fas-bearing lymphocytes. Coexpression of Fas with FasL also suggests that TCC may hare pathways resistant to Fas-mediated aut ocrine cell, suicide.