Expression of ps2 protein and estrogen and progesterone receptor status in breast cancer

OBJECTIVE: To investigate pS2 protein expression and estrogen (ER) and progesterone receptor (PR) status of imprints from surgical biopsies of breast cancer cases in relation to the histologic grade of malignancy. STUDY DESIGN: The study group consisted of 50 cases of primary breast carcinomas. For the demonstration of pS2 protein expression an immunocytochemical avidin-biotin complex technique was applied. Monoclonal antibody pS2 was used as the primary antibody, diaminobenzidine as the chromogene and hematoxylin as the counterstain. For the evaluation of ERs and PRs, a biochemical method was applied. RESULTS: Sixty-two percent of breast cancer cases showed positive expression of pS2. Of the 31 pS2+ cases, 74% had positive ERs and PRs. A statistically significant difference was observed between pS2 protein expression, ER+, PR+ and histologic grade of malignancy (P ’ .001). CONCLUSION: Two groups of breast cancer cases can be distinguished: one group that is ER+, PR+ and pS2+, with low malignancy potential, and another group that is ER1, PR1 and pS21, with high malignancy potential. © 1997 The International Academy of Cytology Acta Cytologica.