The diagnostic value of p27 in comparison to p57 in differentiation between different gestational trophoblastic diseases.

The histologic features that permit the identification of complete mole (CM) and partial mole (PM) as well as hydropic abortion (HA) may be overlapping. The cyclin-dependent kinase inhibitor p57Kip2 protein (p57) has been included among the paternally imprinted genes in humans that commonly used for diagnosis of CM. P27 is one of the cell-cycle controlling molecules that may be involved in the proliferation, differentiation and oncogenesis of trophoblastic cells. The current study tried to test the diagnostic validity of several histopathological parameters together with p57 and p27 immunostaining in differentiation between different gestational trophoblastic diseases. The current study was carried out on 13 cases product of conception, 13 cases PM, 25 cases CM and 8 cases choriocarcinoma. Maximal villous diameter at 1.5 mm cut-off point was found to be the most reliable factor in discrimination between PM and product of conception followed by presence of villous cistern, p57 expression by extravillous cytotrophoblasts at 1.5% cut-off point and p27 expression by villous cytotrophoblasts at 25% cut-off point. P27 expression by stromal cells and total trophoblastic population at 7.5% cut-off point could discriminate between PM and CM. P57 and p27 are co-parallely expressed in non-molar as well as partial molar gestations, but they did not show this coordination in choriocarcinoma. This study demonstrated diagnostic values for several cut-off points for p57 and p27 in discrimination between different categories of gestational trophoblastic diseases. The co-expression of p27 and p57 by extravillous cytotrophoblasts and their positive correlation in non-molar gestations may indicate its suppressive role on the proliferation of these cells to provide them the capacity for differentiation and invasion.