EXPRESSION OF CATHEPSIN-D MESSENGER-RNA IN OVARIAN NEOPLASIA - DEMONSTRATION BY NON ISOTOPIC IN-SITU HYBRIDIZATION AND IMMUNOHISTOCHEMISTRY

The gene expression and distribution of cathepsin D were assessed in a series of 26 ovarian surgical specimens using non isotopic in situ hybridisation and immunohistochemistry. Presence of cathepsin D mRNA and protein was verified in 80% of benign ovarian tumors. Cathepsin D mRNA levels were present in 95% and proteins in 71% of malignant tumors. Cathepsin D had a focal and patchy distribution. In more than 10% of the cancer cells, it was localized prevalently at the edge of the tumor, in the cytoplasm of the malignant epithelial cells and in the macrophages adjacent to tumour. Cathepsin D did not appear to significantly correlate to the stage or grading of ovarian carcinomas. However, cathepsin D antigen seems to be expressed more in well- and moderately-differentiated tumours rather than in poorly-differentiated tumours. Our study appears to confirm that in ovarian neoplasia cathepsin D is overexpressed. The cathepsin D overproduction may increase the metastatic potential of ovarian neoplasms by degrading the baement membrane and extracellular matrix. The preferential expression of secreted cathepsin at tumour edge, indicates that cathepsin D has a role in the malignant progression of ovarian carcinomas. The invasiveness of the tumour could depend on the ratio between the stromal and inflammatory components. In conclusion, even though cathepsin D does not appear to correlate with stage, histotype or grading, it should be useful in predicting the risk of local recurrence and spread of disease.