Immunohistochemical study of the BCAR1/p130Cas protein in non-malignant and malignant human breast tissue

Int J Biol Markers. Jul-Sep 2001;16(3):172-8.


BCAR1/p130Cas is a docking protein involved in intracellular signaling pathways and in vitro resistance of estrogen-dependent breast cancer cells to antiestrogens. The BCAR1/p130Cas protein level in primary breast cancer cytosols was found to correlate with rapid recurrence of disease. A high BCAR1/p130Cas level was also associated with a higher likelihood of resistance to first-line tamoxifen treatment in patients with advanced breast cancer. Using antibodies raised against the rat p130Cas protein, we determined by immunohistochemical methods the BCAR1/p130Cas localization in primary breast carcinomas, in tumors of stromal origin, and in non-neoplastic breast tissues. The BCAR1/p130Cas protein was detected in the cytoplasm of non-malignant and neoplastic epithelial cells and in the vascular compartment of all tissue sections analyzed. Immunohistochemistry demonstrated variable intensity of BCAR1/p130Cas staining and variation in the proportion of BCAR1/p130Cas-positive epithelial tumor cells for the different breast carcinomas. Double immunohistochemical staining for BCAR1/p130Cas and estrogen receptor confirmed coexpression in non-malignant luminal epithelial cells and malignant breast tumor cells. The stromal cells in non-malignant tissues and tumor tissues as well as breast tumors of mesodermal origin did not stain for BCAR1/p130Cas. This immunohistochemical study demonstrates a variable expression of BCAR1/p130Cas in malignant and non-malignant breast epithelial cells, which may be of benefit for diagnostic purposes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Breast / chemistry*
  • Breast Neoplasms / blood supply
  • Breast Neoplasms / pathology*
  • Carcinoma, Intraductal, Noninfiltrating / pathology
  • Crk-Associated Substrate Protein
  • Epithelial Cells / cytology
  • Epithelial Cells / pathology
  • Female
  • Humans
  • Immunohistochemistry
  • Middle Aged
  • Neoplasm Invasiveness
  • Phosphoproteins / analysis*
  • Proteins*
  • Retinoblastoma Protein / analysis*
  • Retinoblastoma-Like Protein p130
  • Stromal Cells / cytology
  • Stromal Cells / pathology


  • BCAR1 protein, human
  • Crk-Associated Substrate Protein
  • Phosphoproteins
  • Proteins
  • Retinoblastoma Protein
  • Retinoblastoma-Like Protein p130