[Preoperative immunocytochemical estrogen receptor determination in fine needle aspirates in breast cancer using monoclonal antibodies].

The biochemical detection of ER in breast cancer is of high value for the prognosis and planning of treatment. The conventional biochemical assays of ER are expensive, time-consuming and give little information on the topography and heterogeneity of receptor-protein in the tissue. Observations of different study groups showed a good correlation between the results of the biochemical assay and the monoclonal method in frozen sections. This ER-detection method was used on 34 fine needle aspirates from patients with breast cancer. 30 samples (88.2%) contained sufficient cells for analysis. The value of this method was proven and the results correlated to the measurement resulting from the biochemical assay. In 24 of the 30 fine needle aspirates we found good semi-quantitative correlation between the biochemical assay and the monoclonal method. Cytology, including ER-detection, permits definition not only of the receptor state, but also of the definition of the tumor. The employment of ER-detection in fine needle aspirates is useful in the following cases: Small tumors, which do not supply enough tissue to practice all in vitro tumor tests, as well as in metastasising tumors, in which surgical intervention or histological confirmation is not always necessary. The preoperative knowledge of ER may soon permit a different surgical therapy.