Immunohistochemical analysis of estrogen receptors in cells obtained by fine needle aspiration from human mammary carcinomas.

An immunocytochemical assay for the estrogen receptor has been used to analyze the receptor content in tumor cells obtained by fine needle aspiration from human breast carcinomas. The results were compared with receptor determinations on cryostat sections of freshly frozen tumors and by biochemical technique based on radiolabelled ligand binding. The staining intensity and fraction of positive cells were comparable in cryostat sections and tumor cell specimens obtained by fine needle aspiration. Moreover, there was a good correlation between the semiquantitative receptor level estimated by the immunoperoxidase technique and the biochemical assay. These results show that tumor cell specimens obtained by fine needle aspirates can be used for estrogen receptor analysis by the immunocytochemical technique.