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

• Published in: The International journal of biological markers 2001-07, Vol.16 (3), p.172-178
• Main Authors: VAN DER FLIER, S, VAN DER KWAST, T. H, CLAASSEN, C. J. C, TIMMERMANS, M, BRINKMAN, A, HENZEN-LOGMANS, S. C, FOEKENS, J. A, DORSSERS, L. C. J
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Breast - chemistry; Breast Neoplasms - blood supply; Breast Neoplasms - pathology; Carcinoma, Intraductal, Noninfiltrating - pathology; Crk-Associated Substrate Protein; Epithelial Cells - cytology; Epithelial Cells - pathology; Female; Gynecology. Andrology. Obstetrics; Humans; Immunohistochemistry; Mammary gland diseases; Medical sciences; Middle Aged; Neoplasm Invasiveness; Phosphoproteins - analysis; Proteins; Retinoblastoma Protein - analysis; Retinoblastoma-Like Protein p130; Stromal Cells - cytology; Stromal Cells - pathology; Tumors
• ISSN: 0393-6155; 1724-6008
• DOI: 10.1177/172460080101600303

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.