Prognostic value of Cathepsin D expression in breast cancer: Immunohistochemical assessment and correlation with radiometric assay

Abstract

Background: The prognostic significance of Cathepsin D and optimal methodologies to measure Cathepsin D in breast cancers are controversial. Patients and methods: Quantitative (immunoradiometric) and semiquantitative (immunohistochemical) assays for Cathepsin D expression were compared using 25 breast carcinomas. Immunohistochemical Cathepsin D results were derived using 3 different anti-Cathepsin D antibodies and significant associations between immunohistochemical and radiometric Cathepsin D data were observed for each reagent. Immunohistochemical analysis of Cathepsin D expression was performed on nearly 500 fixed-embedded archival breast cancers with long-term patient follow-up using 2 anti-Cathepsin D antibodies (CDR2-11/23, IC11). Results: The immunohistochemical reagents recognized generally overlapping subsets of Cathepsin D positive tumors (correlation co-efficient 0.54; p - 0.00016). Correlations between Cathepsin D data and clinical, histologic or biologic features differed for each antibody. For the node-negative patient subset, Cathepsin D immunopositivity correlated with erbB-2 and stress-response protein 27 overexpression but not survival. Cathepsin D positivity was associated with subsequent distant metastasis and estrogen receptor positivity in node positive patients. Univariate analysis of all patients suggested that Cathepsin D immunopositivity may be predictive of a reduced metastasis-free but not overall survival. Multivariate analysis, however, failed to confirm an independent prognostic value for Cathepsin D in breast cancer patients. Conclusions: These data do not confirm an independent prognostic significance for Cathepsin D using immunohistochemical methods on breast cancers. © 1994 Kluwer Academic Publishers.