Expression of Pro-Apoptotic Bax and Anti-Apoptotic Bcl-2 Proteins in Hydatidiform Moles and Placentas With Hydropic Changes

Abstract

Abstract- Morphologic examination still forms the main diagnostic tool in the differential diagnosis of molar placentas. However the criteria are subjective and show considerable inter-observer variability among pathologists. The aim of the present study was to investigate the role of Bcl-2 and Bax immunostaining in the differential diagnosis of molar placentas. Bax and Bcl-2 immunohistochemical staining were performed in 19 molars (8 partial and 11 complete hydatidiform mole) and 10 non-molar (hydropic abortion) formalin-fixed, paraffin-embedded tissue samples. Ploidy analysis using flow cytometry had confirmed diploidy in hydropic abortions and complete hydatidiform moles and triploidy in partial hydatidiform moles. Bcl-2 expression was observed only in syncytiotrophoblasts, No immunoreactivity was detected in Cytotrophoblasts, and stromal cells, the total score averages of Bcl-2 immunoexpression in partial hydatidiform moles and hydropic abortions were significantly higher than in complete hydatidiform moles, whereas no significant difference was observed between partial hydatidiform moles and hydropic abortions. Bax immunoreactivity was observed in cytotrophoblasts, stromal cells and occasionally in syncytiotrophoblasts. No statistically significant difference in Bax immunoexpression total score was observed among various groups. Based on the results of this study, Bcl-2 immunostaining offers a potential adjunctive diagnostic tool to distinguish complete hydatidiform mole from partial hydatidiform mole and hydropic abortion, but not partial hydatidiform mole from hydropic abortion, Bax immunostaining cannot be helpful in this regard.