Trophoblast apoptosis in placentas from pregnancies complicated by preeclampsia S. Zekic Tomas * , I. Kuzmic Prusac, D. Roje, I. Tadin * Clinical Hospital Centre Split, Pathology, Croatia Objective: To assess trophoblast apoptosis separately in cytotrophoblast, syncytiotrophoblast, total villous trophoblast and syncytial knots, as well as to investigate the expression of apoptotic factors Fas ligand (FasL), Bcl-2 and proliferation marker Ki-67 in trophoblast of placentas from preeclamptic patients. Method: The study included placental samples from 25 preeclamptic and 25 normal pregnancies. For the detection of apoptosis and proliferation antibody M30 and antibody against Ki-67 antigen were used. Expression of Fas ligand and Bcl-2 was assessed using semi quantitative HSCORE method. Syncytial knots were expressed as the number of syncytial knots per individual villus and as the total number of syncytial knots in each placental sample.