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

Int J Cancer. 1995 Mar 3;60(5):597-603. doi: 10.1002/ijc.2910600505.


We used an immunohistochemical assay with an antigen-retrieval technique to study plasminogen activator inhibitor type-1 (PAI-1) expression in paraffin-embedded breast tissue samples at different stages of malignant transformation. We detected PAI-1 in 15/20 invasive tumors. In several cases staining was localized to the stromal component. PAI-1-positive fibroblasts could be seen surrounding tumor nodules or at tumor margins. In addition, tumor-infiltrating macrophages (13 cases) and endothelial cells (5 cases) were positive. In 11 specimens PAI-1-positive cancer cells were also detected. In 2 strongly positive cases secreted PAI-1 was visible in the extracellular 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. PAI-1 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 PAI-1 in all cases examined. In addition, production of PAI-1 by the tumor stroma could protect the tumor itself from excessive proteolysis.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Breast / chemistry
  • Breast / cytology
  • Breast Neoplasms / chemistry*
  • Breast Neoplasms / pathology
  • Carcinoma / chemistry
  • Carcinoma / pathology
  • Carcinoma in Situ / chemistry
  • Carcinoma in Situ / pathology
  • Cells, Cultured
  • Fibroblasts / chemistry
  • Fibrosarcoma / chemistry
  • Fibrosarcoma / pathology
  • Fluorescent Antibody Technique
  • Immunoenzyme Techniques
  • Molecular Sequence Data
  • Neoplasm Invasiveness
  • Neoplasm Proteins / analysis*
  • Neovascularization, Pathologic
  • Papilloma / chemistry
  • Papilloma / pathology
  • Plasminogen Activator Inhibitor 1 / analysis*
  • Pleural Effusion / chemistry
  • Pleural Effusion / pathology
  • Subcellular Fractions / chemistry*
  • Tumor Cells, Cultured
  • Urokinase-Type Plasminogen Activator / analysis


  • Neoplasm Proteins
  • Plasminogen Activator Inhibitor 1
  • Urokinase-Type Plasminogen Activator