Utility of p57 protein(KIP2) in molar disease to determine its androgenetic origin

To determine, qualitatively and semiquantitatively, the expression of p57 protein in different trophoblastic cell populations of hydatidiform mole and anembryonic pregnancy.

We performed an observational study of the histopathologic and immunohistochemical findings of 48 cases of hydatidiform mole and 2 anembryonic pregnancies. The histologic samples stained with hematoxylin-eosin were reviewed blindly by 3 pathologists to establish a diagnosis and compare it to the previous one. Afterward, immunohistochemical staining was performed using a polyclonal antibody on paraffin-embedded, formalin-fixed tissue sections. The nuclear staining was assessed in 5 cell types: villous mesenchyme, cytotrophoblast, syncytiotrophoblast, intervillous trophoblast and decidua.

The degree of agreement between the previous histologic diagnosis and the current one was excellent (kappa = 0.702). The sensitivity was 82.6% for complete and 84% for partial mole. On immunohistochemical analysis, the degree of agreement was low (kappa = 0.2). The sensitivity was 53.9% for complete mole and 59.1% for partial mole. The cell population with the least expression for p57 was the cytotrophoblast. The results for anembryonic pregnancies remained the same.

Immunohistochemistry with p57 is a useful method to differentiate complete from partial mole, which is important to establish the prognosis of the patient.