Immunohistochemical expression of cathepsin D in correlation with extracellular matrix component, steroid receptor status and proliferative indices in breast cancer.

In 87 breast cancer patients, the immunohistochemical expression of the basement membrane (BM)-degrading enzyme cathepsin D (CD) was correlated with the expression of extracellular matrix components, with growth fraction, steroid receptor content and with the other conventional prognostic variables in breast cancer. Only 6.25% of tumours had laminin-defined BM, while 86.8% showed staining for fibronectin. CD was also identified in carcinoma cells (cancer cell CD; CCCD) and in stromal cells (stromal cell CD; SCCD). Forty-five percent of tumours showed CCCD and 47.5%, SCCD expression. CCCD expression was significantly correlated with positive oestrogen receptor content, with low Ki-67 and high PCNA score and with SCCD expression. There was no correlation with collagen type IV, laminin or fibronectin. SCCD expression was positively correlated with collagen type IV, laminin expression and tumour grade. The data suggest that the CD of tumour cells and the CD of tumour-associated macrophages have different roles in breast cancer. CCCD correlates with cell proliferation and is regulated by oestrogens, while SCCD relates to cell differentiation, is oestrogen-independent, and has a proteolytic role in the breakdown of BM components.

Immunohistochemical localization of metallothionein in human breast cancer in comparison with cathepsin D, stromelysin-1, CD44, extracellular matrix components, P53, Rb, C-erbB-2, EGFR, steroid receptor content and proliferation.

Metallothionein (MT) is a low molecular weight, cysteine-rich, zinc-binding protein that may have a function in cellular repair processes, growth and differentiation. Using a monoclonal antibody (E9) to metallothionein, we investigated the immunohistochemical expression of MT in routinely fixed and paraffin-embedded tissue from 98 cases of female breast carcinomas. The MT expression was studied in comparison with the expression of the basement membrane (BM) antigens (type IV collagen, laminin), fibronectin, cathepsin D, adhesion molecule CD44, p53 protein, the pRb, c-erbB-2 oncoprotein, EGFR, stromelysin-1, proliferation indices (Ki-67, PCNA), steroid receptor content as well as with other conventional clinicopathological parameters of breast cancer. Strong MT expression was observed in the majority of tumour cells in 18.4% of tumours, focal MT positivity in 13.3% and almost complete lack of MT expression in 68.4% of cases (mean value 33.36 +/- 26.36). The MT expression in carcinoma cells was strongly associated with the DCIS component of the tumour (p < 0.0001). High values of MT were correlated with low steroid receptor status (p = 0.08 for ER receptor and p = 0.019 for PgR receptor content). MT positive cases were correlated with stromelysin-1 expression (p = 0.059) and cathepsin D (p = 0.058). These findings suggest that MT expression is characteristic of the early phase of breast carcinogenesis, possibly regulated by hormones, and could be a new potential prognostic marker in breast cancer.