IMMUNOHISTOCHEMICAL DETECTION OF CATHEPSIN-D IN LOW-GRADE BREAST INVASIVE CANCER

Background: Cathepsin D (CatD) can facilitate the invasive behaviour o f breast cancer cells and thus plays a key role in the mechanism of in vasion and metastasis. Materials and Methods: The expression of the pr otease CatD was evaluated using an immunohistochemical technique with a polyclonal antibody on paraffin-embedded tissue from 80 women treate d for invasive ductal mammary carcinoma not otherwise specified (NOS). Results: Thirty seven tumours (46%) showed prominent staining of cell s in the tumour: Neoplastic cell staining for CatD correlated with axi llary nodal involvement (p<0.05), high oestrogen receptor positivity s tatus (p<0.01) ann low or moderate tumour grade (p<0.05). Stromal cell (primarily histiocyte) CatD immunostaining was frequently noticed and was proportional to the degree of the intratumoural inflammatory infi ltrate. Conclusions: CatD detection in neoplastic cells is likely to b e involved in the invasive capability of well differentiated breast ca ncer cells, but it may simultaneously reflect the functional integrity of the oestrogen response pathway, commonly observed in well-differen tiated tumours.