Immunohistochemical study of the BCAR1/p130Cas protein in non-malignant and malignant human breast tissue.
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.
van der Flier
S
S
Department of Pathology, Josephine Nefkens Institute, University Hospital Rotterdam/Daniel den Hoed Cancer Center, The Netherlands.
van der Kwast
T H
TH
Claassen
C J
CJ
Timmermans
M
M
Brinkman
A
A
Henzen-Logmans
S C
SC
Foekens
J A
JA
Dorssers
L C
LC
D000328:Adult; D001940:Breast / Q000737:chemistry*; D001943:Breast Neoplasms / Q000098:blood supply / Q000473:pathology*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology; D050719:Crk-Associated Substrate Protein; D004847:Epithelial Cells / Q000166:cytology / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010750:Phosphoproteins / Q000032:analysis*; D011506:Proteins; D016160:Retinoblastoma Protein / Q000032:analysis*; D050717:Retinoblastoma-Like Protein p130; D017154:Stromal Cells / Q000166:cytology / Q000473:pathology
C493841:BCAR1 protein, human; D050719:Crk-Associated Substrate Protein; D010750:Phosphoproteins; D011506:Proteins; D016160:Retinoblastoma Protein; D050717:Retinoblastoma-Like Protein p130