GATA3 expression in gestational trophoblastic tissues and tumours.

AIMS GATA3 is a zinc-finger transcription factor that is important for trophoblast differentiation. GATA3 is sensitive for urothelial and breast carcinomas, but the specificity is low. The aim of this study was to investigate the expression of GATA3 in trophoblast-related tissues and neoplasia. METHODS AND RESULTS GATA3 immunohistochemistry was performed on 33 placentas, one atypical placental site nodule, 25 hydatidiform moles (HMs), and 13 gestational trophoblastic tumours (GTTs). One hundred and sixty endometrial adenocarcinomas were also stained. Western blotting was performed on trophoblastic cell lines and compared to other cancer cell lines. Immature placentas were characterized by strong, diffuse nuclear GATA3 staining. Mature placentas showed less expression with scattered positive cells in the villous cytotrophoblast. HMs showed diffuse expression in cytotrophoblast and implantation site trophoblast, and heterogeneous expression in extravillous trophoblast. All GTTs were positive for GATA3. All endometrial adenocarcinomas were GATA3-negative. Western blotting demonstrated GATA3 in choriocarcinoma, whereas the placenta, and cervical and endometrial cancer cell lines, were negative. CONCLUSIONS All trophoblast lineages were positive for GATA3. The extent of GATA3 expression varied between immature and mature placentas, suggesting a role in trophoblast maturation. GATA3 does not distinguish normal placenta, HMs, or GTTs. Nevertheless, GATA3 may help in distinguishing trophoblastic tumors from Mullerian epithelial malignancies and a subset of tumours of unknown origin.