ELEVATED LEVELS OF PRO-CATHEPSIN-D IN THE PLASMA OF BREAST-CANCER PATIENTS
Changes in the expression and processing of cathepsin D (CD) have been shown to be associated with cancer invasion and metastasis. However, the value of CD as a prognostic marker remains controversial. Most studies have used immunological methods to measure the mature form of CD, although it is the precursor (pro-CD) that appears to be abnormally secreted by breast cancer cells. A sandwich-type ELISA has been developed that is specific for pro-CD. The assay employs a monoclonal antibody to mature CD as the capture reagent and a rabbit polyclonal to the pro fragment as the detector. The assay is specific for pro-CD and capable of quantitating this antigen in biological samples. Pro-CD levels were measured in plasma samples from 76 breast cancer patients and compared with 36 samples from normal control individuals. The plasmas of breast cancer patients showed elevated levels of pro-CD; 12% were more than two standard deviations above the mean for the normal samples. Immunoblots of the plasma samples using a CD monoclonal antibody revealed a band at the appropriate size for pro-CD that corresponded in intensity with the ELISA results. Affinity adsorption of breast cancer plasmas with pepstatin agarose followed by immunoblot analysis revealed a single protein band that correlated with pro-CD. Only trace amounts were detected in the normal control plasmas. These results demonstrate that cathepsin D is present in the plasma of breast cancer patients primarily in its precursor form and that it may be a useful prognostic indicator.
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Document Type: Research Article
Affiliations: ONCOGENE SCI INC,CAMBRIDGE,MA 02142.
Publication date: April 1, 1995
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- The International Journal of Oncology provides an international forum for the publication of the latest, cutting-edge research in the broad area of oncology and cancer treatment. The journal accepts original high quality works and reviews on all aspects of oncology research including carcinogenesis, metastasis, epidemiology, chemotherapy and viral oncology. Through fair and efficient peer review, the journal is dedicated to publishing top tier research in the field, offering authors rapid publication as well as high standards of copy-editing and production. The International Journal of Oncology is published on a monthly basis in both print and early online.
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