Immunocytochemical analysis of receptors for estrogen and progesterone in fine-needle aspirates from human breast carcinomas.

Monoclonal antibodies were used for a preoperative analysis of estrogen receptors (ERs) and progesterone receptors (PgRs) in fine-needle aspirates from 44 primary human breast carcinomas. The semiquantitative receptor values obtained in cytologic specimens correlated well with those from enzyme immunoassay analysis on surgically removed tumor tissue (r = 0.74 for PgR; r = 0.75 for ER). Cytologic smears showed a heterogenous tumor cell distribution of ER and PgR in 29 and 23 cases, respectively. The results suggest that measurement of the ER and PgR in cytologic smears is an accurate and reliable technique that can be performed on a minimum amount of tissue.