Stromal cell cathepsin D expression and long-term survival in breast cancer

Breast cancers with an increased level of cathepsin D in tumour tissue extract have been found to have poor prognosis, but studies performed with immunohistochemistry have produced variable results. We analysed 213 primary invasive breast cancers for cathepsin D expression from archival tissue with immunohistochemistry. The minimum follow-up of the patients still alive was 26 years. Women with ductal cancer that lacked cathepsin D expression in stromal macrophage-like cells had a 75% 5 year and 55% 30 year survival rate as compared with only a 40% 5 year and 20% 30 year survival rate if stromal cells expressed cathepsin D (P = 0.0003), whereas cathepsin D expression of cancer cells was associated with neither survival nor the several prognostic factors investigated. Stromal cell cathepsin D was more often present in the ductal than in the lobular histological type (80% vs 54%, P = 0.002), and its expression was strongly associated particularly with a high cell proliferation rate. However, in a multivariate analysis stromal cell cathepsin D expression did not have independent influence on survival in the entire series. We conclude that high stromal cell cathepsin D expression is associated with a poor short- and long-term outcome in breast cancer.