LOCALIZATION OF PLATELET-DERIVED GROWTH-FACTOR-BETA RECEPTOR EXPRESSION IN THE PERIEPITHELIAL STROMA OF HUMAN BREAST-CARCINOMA

Platelet-derived growth factor (PDGF) BB is secreted by most human bre ast carcinoma cells; however, only recently have PDGF beta receptors b een demonstrated in malignant breast tissue, In the present study, the tissue localization of PDGF beta receptor expression was studied in h uman breast carcinoma and nonmalignant breast tissues stained using bo th immunofluorescence and immunoperoxidase techniques, We examined a t otal of 29 cases of breast carcinomas, which showed both in situ and i nvasive components, PDGF beta receptor staining was localized in the p eriepithelial stroma and was particularly intense in regions immediate ly adjacent to carcinoma in situ components in all tumors examined, A diffuse low level of PDGF beta receptor staining was seen throughout t he stroma of eight nonmalignant breast tissues as well as of nonmalign ant regions of tumor tissues, Image analysis was used to assess the co incidence of staining of PDGF beta receptor with epithelial or stromal cells in 13 of the 29 tumor tissues studied, Less than 5% of malignan t ductal epithelium or myoepithelium showed PDGF beta receptor stainin g, Analysis with stromal cell type-specific markers indicated signific ant localization of PDGF beta receptor primarily within alpha smooth m uscle actin-staining cells (32%) and vascular endothelial cells (41%) in the periepithelial stroma, PDGF beta receptor positivity was strong ly associated with periepithelial stromal cells adjacent to the baseme nt membrane surrounding regions of carcinoma in situ but was less inte nse in regions of invasive carcinoma where basement membrane was degra ded, The absence of PDGF beta receptors on carcinoma cells and their p resence in the surrounding stroma suggest a paracrine stimulation of a djacent stromal tissue by malignant epithelial cells in human breast t umors.