The significance of proliferating cell nuclear antigen in human trophobiastic disease: an immunohistochemical study

The expression of proliferating cell nuclear antigen (PCNA) in human trophobiastic disease was assessed immunohistochemically in tissue from 29 spontaneous abortions, 33 partial moles, 40 complete moles and 23 chorio carcinomas using the monoclonal antibody PC ID. PCNA immunoreactivity occurred predominantly in the cytotrophoblasts in each of the four types of tissues. Quantitative analysis showed that the choriocarcinoma group gave a statistically significant higher PCNA index than the other three. There was no significant difference between the groups of spontaneous abortion, partial or complete mole. Sixteen of the 73 patients with partial and complete moles developed persistent gestational trophobiastic disease and there was no significant difference between the patients requiring chemotherapy and those who did not. We conclude that choriocarcinoma has a significantly higher PCNA proliferative index whilst hydatidiform moles cannot be distinguished from abortions by such analysis. The PCNA index does not appear to be useful in predicting the progression of molar pregnancies to persistent trophobiastic diseases.