Objectives: The purpose of this study was to identify prognostic biomarkers indicating malignant transformation of hydatidiform moles (HMs).

Methods: Two-dimensional gel electrophoresis-based proteomic approach was used to compare the protein profiles of complete benign moles (3 samples) with those of malignant-transformed moles (3 samples). Matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify differentially expressed proteins. Western blot was used to verify the results of 2-dimensional gel electrophoresis, and immunohistology was used to explore the function of these proteins in gestational trophoblastic disease.

Results: Eighteen proteins, deregulated in the malignant-transformed group compared with the benign group (ratio ≥2; P < 0.05), were identified. A bioinformatic analysis indicated that most of these 18 proteins were involved in the processes of cell proliferation and cell survival. Among the 18 proteins, chloride intracellular channel protein 1 (CLIC1) was chosen for further study. Our results showed that the levels of CLIC1 expression in choriocarcinoma tissue were higher than in complete HM tissue (P < 0.01). Chloride intracellular channel protein 1 expression was increased in the tissues of malignant-transformed HMs compared with nontransformed HMs (P < 0.01).

Conclusion: Our findings suggest that CLIC1 could be a potential new prognostic biomarker for hydatidiform mole that undergoes malignant transformation.