Serum levels of Hemorphin-7 peptides in patients with breast cancer

Background: Increased expression of cathepsin D (CD) and B (CB) is found in some cancers and correlates with the development of clinical metastases. It was suggested that these cathepsins Could be used as prognostic markers, especially CD in breast cancer. Because serum level of Hemorphin-7 (H7) peptides could reflect CID activity, we have hypothesised that it could be used as a prognostic factor in breast cancer. Methods: To verify this hypothesis, H7 serum levels from 62 breast cancer patients and 25 healthy controls were measured by ELISA. Results: The mean serum concentration of H7 was 2.27 +/- 0.63 mumol/l in breast cancer patients in comparison with 4.09 +/- 1.05 mumol/l in controls (p = 0.002). This reduced level of H7 in breast cancer could be due to the over-expression of CB, which exhibits strong interaction with H7 in vitro, with a ratio K-cat/K-m estimated at 18,000 s(-1) M-1. Conclusions: Because H7 serum levels did not correlate with other parameters including age, CA15-3 and ACE markers, it seems that they might be used as independent markers for the diagnosis of breast cancer. (C) 2003 Elsevier B.V. All rights reserved.