Expression and subcellular localization of maspin in human ovarian epithelial neoplasms: correlation with clinicopathologic features.

BACKGROUND AND PURPOSE

Maspin is an inhibitor of serine proteinases with tumor suppressor activity that is down-regulated in breast and prostate cancer, but overexpressed in pancreatic carcinoma. However, there were very few published data regarding the role of maspin in ovarian carcinoma. The aim of the present study was to evaluate maspin expression in ovarian epithelial neoplasms and correlate its expression with some clinicopathologic parameters.

MATERIAL AND METHODS

Seventy eight paraffin embedded ovarian specimens from patients with ovarian epithelial neoplasms comprised the material of this study. They included 18 benign, 14 low malignant potential (LMP) and 46 malignant epithelial ovarian neoplasms, in addition to seven specimens from normal ovarian tissues as a control.

RESULTS

Immunohistochemical study of maspin expression using streptavidin biotin immunoperoxidase method revealed that, normal ovarian surface epithelium did not express maspin as well as benign serous and mucinous ovarian epithelial neoplasm. However, all benign Brenner ovarian tumors were maspin positive. On the other hand, 57.14% of LMP tumors showed weak maspin expression and 63% of malignant ovarian epithelial tumors showed maspin expression with 39.1% over expression. The two malignant Brenner tumors studied were maspin negative. There was a trend for maspin expression with high grade, high stage, bilateral tumors and tumors with metastasis. Tumors that showed maspin over-expression showed higher mitotic index (MI) (p=0.02). Invasive cancers were more likely to have predominantly cytoplasmic staining compared to LMP tumors.

CONCLUSION

Maspin was expressed in a substantial proportion of ovarian tumors with poor prognostic parameters. These results may offer new insights regarding the role of maspin in ovarian cancer that may also impact diagnosis and treatment strategies. Moreover, variation in maspin expression between Brenner tumor and other epithelial surface ovarian tumors may indicate that the different histological types probably represent distinct disease entities and involve different molecular pathways.