Abstract: Objective: To investigate the expression of MASPIN in gestational trophoblastic tumor （GTT）, and the role of MASPIN in GTT. Methods: Forty inpatients with gestational trophoblastic disease（GTD） were recruited in the study, including 30 patients with hydatidiform mole, 10 with GTT. and 20 normal chorion were taken as control. Immunohistochemistry was used to analyze MASPIN expression in GTD and normal chorion. Results: The gestational trophoblastic tumor MASPIN positive expression rate（10%, 1/10） was significantly lower than the control group （95%, 19/20）, the two groups, the difference was statistically significant（P <0.05）. Hydatidiform mole group MASPIN positive rate （60%, 18/30） was significantly lower than the control group （95%, 19/20）, （P <0.05）. Gestational trophoblastic tumor MASPIN expression was significantly lower than that of hydatidiform mole group（P <0.05）. Conclusion: The down-regulation of the MASPIN expression is involved in the development of GTD, and may paly an important role in the pathogenesis of GTD.

Key words: Gestational trophoblastic tumor, Hydatidiform mole, MASPIN, Invasion, Immunohistochemistry, Serine protease inhibitor