Immunohistochemical localization of the plasminogen activator inhibitor-1 in breast cancer

✍ Scribed by Elisabetta Bianchi; Robert L. Cohen; Aihua Dai; Ann T. Thor; Marc A. Shuman; Helene S. Smith

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: French
• Weight: 848 KB
• Volume: 60
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910600505

✦ Synopsis

We used an immunohistochemical assay with an antigenretrieval technique to study plasminogen activator inhibitor type-I (PAL I) expression in paraffin-embedded breast tissue samples at different stages of malignant transformation. We detected PAI-I in 15/20 invasive tumors. In several cases staining was localized to the stromal component. PAL I -positive fibroblasts could be seen surrounding tumor nodules or at tumor margins. In addition, tumor-infiltrating macrophages (I 3 cases) and endothelial cells (5 cases) were positive. In I I specimens PAI-I -positive cancer cells were also detected. In 2 strongly positive cases secreted PAI-I was visible in the extracel-Mar matrix surrounding the cells. Six of 9 samples of carcinoma in situ (DCIS) were weakly positive. No staining of endothelial cells was visible in DCIS. Only a few positive adenomatous epithelial cells could be seen in 3 of 7 papillomas. All biopsies of normal breast tissue were negative, with the exception of one sample, obtained from a patient with a previous segmental mastectomy for DCIS. PAL I production by invasive breast cancers could reflect a general upregulation of the plasminogen activation system in proliferating cancer cells, as suggested by the finding that normal mammary epithelium cultures expressed PAL I in all cases examined. In addition, production of PAL I by the tumor strorna could protect the tumor itself from excessive proteolyris.