The Expression of G1-S Cell Cycle Inhibitors in Normal Placenta and Gestational Trophoblastic Diseases

ABSTRACT

BACKGROUND: The objective of this study is to determine the expression pattern of G1-S inhibitor molecules in normal trophoblasts and gestational trophoblastic diseases, including hydatidiform moles and choriocarcinoma. METHODS: A total of 157 cases comprising 47 normal placentas and 110 gestational trophoblastic diseases such as choriocarcinoma (19 cases) and hydatidiform moles (91 cases of which 58 were complete, 12 were partial and 21 were invasive mole) were immunohistochemically analyzed on paraffin blocks using anti-p21, antip27, anti-p16, anti-p53, anti-pRb antibodies. RESULTS: The results revealed that in the normal placenta, all the G1-S cell cycle inhibitors were maximally expressed by the first-trimester trophoblasts and these levels decreased with gestational age. The expression of p21 and p53 was greatly enhanced in the gestational trophoblastic diseases, particularly in invasive mole and choriocarcinoma, whereas the p27 expression was significantly downregulated in choriocarcinoma. Especially, Rb expression was typically enhanced in the invasive mole, but not in choriocarcinoma. The expression level of p16 was low in all the cases, and particularly in choriocarcinoma. CONCLUSIONS: In conclusion, we demonstrated that the expression of G1/S cell cycle inhibitors correlates well with normal trophoblast differentiation, and these expressions are considerably altered in the gestational trophoblastic diseases, including complete/partial/ invasive hydatidiform mole and choriocarcinoma.