Objectives To analyze the expression patterns of poly(rC)-binding protein 1 (PCBP1) in complete hydatidiform moles (HMs) and to determine the predictive value of PCBP1 during postmolar follow-up after uterine evacuation.

Materials and Methods The PCBP1 protein expression profile was investigated in 10 complete moles that remained benign, 10 complete moles that underwent malignant transformation, and 10 choriocarcinoma tissues using Western blot analysis. The PCBP1 protein expression patterns in complete HM samples gathered from 69 patients were also detected by immunohistochemical analysis. The association of PCBP1 protein expression with the progression in HMs was subsequently assessed.

Results The expression of PCBP1 was significantly lower in malignant-transformed moles than benign moles. The PCBP1 expression level was negatively associated with malignant transformation and serum human chorionic gonadotropin levels. Logistic regression analysis indicated that complete moles with high PCBP1 expression levels had a significantly lower risk of progression to gestational trophoblastic tumors (odds ratio, 0.22; 95% confidence interval, 0.07–0.67).

Conclusions These observations suggest that PCBP1 may be important in the pathogenesis of gestational trophoblastic tumors. In addition to the β-fraction of human chorionic gonadotropin, decreased expression of PCBP1 protein may be a strong predictor of the malignant transformation of complete moles.