Prognostic value of cathepsin-D expression in female breast cancer.

Expression of an acidic lysosomal protease, cathepsin-D (CD), was analysed immunohistochemically in a series of 151 breast carcinomas with special reference to its prognostic significance, Strong expression of CD was detected in 22% of cases. This intense expression was significantly associated with a number of established prognostic factors, including the non-ductal type of carcinoma (p = 0.0243) and metastases at the time of diagnosis (p = 0.0068). On the other hand, high expression of CD was not related to the lymph-node status, tumour size, ER/PR content or histological grade. Patients with CD overexpression has a significantly lower survival probability (p = 0.0478) than did the patients with low expression of this protease. The relationship between the high expression of CD and short disease-free survival was almost significant (p = 0.0519). Intense immunostaining of CD was associated with a significantly impaired disease outlook in patients with confirmed lymph node metastasis (N+) (p = 0.0137) but not in those with negative lymph nodes (N-) (p = 0.0620). In Cox's multivariate analysis, expression of CD had no independent prognostic value over the conventional prognostic factors. The results suggest that expression of CD is of borderline significance in evaluating the intrinsic malignancy of female breast cancer in general. The potential of CD as a prognostic factor in specific subgroups of breast cancers will be the subject of further studies.