engleski

Multinational study of oestrogen and progesterone receptor immunocytochemistry on breast carcinoma fine needle aspirates

The aims of our study were to collect data on the variability of immunocytochemical (ICC) procedures used in estrogen/progesterone (ER/PR) determination on cytological material, to test the reproducibility of results and to determine which procedures influence the outcome of reactions. Ten laboratories from eight countries participated in the study. In the first part, the coordinating laboratory prepared cytospins from an FNA sample of a primary breast carcinoma and distributed them. Participants performed ICC staining for ER/PR according to their own methods on the test slides and on the in-house positive controls. Slides were returned to the coordinator together with the information on the preparation of positive control slides and ICC methodology used. In the second run the preparation and fixation of control slides and antigen retrieval were specified. Evaluation of results included grading the number of positive cells, the intensity of nuclear, background and cytoplasmic staining, sample condition and cellularity of in-house positive control samples. Each participant evaluated their own results, the coordinator evaluated the results from all participants and compared the two evaluations. There was great variability in preparation of slides for in-house controls and in ICC methodology. The outcome of ICC staining of in- house control slides was excellent in two laboratories, adequate in two, sub-optimal in four and inadequate in one. Only six laboratories obtained a positive reaction on the test slides, however, not all of them were of high standard quality. Results of the second run were greatly improved. Cellularity of in-house positive control slides increased while the scores for percentage of stained cells and nuclear staining intensity were higher on the in-house control slides and on the test slides compared to the scores from the first run. There was a great variability at each step of specimen preparation, fixation and ICC staining of hormonal receptors among laboratories. We established that cytospins and monolayer preparations are superior to direct smears and identified the fixation and the antigen retrieval as the key points in the staining process. Inter-laboratory reproducibility of hormonal receptor determination on test slides was not satisfactory. Many laboratories relied on positive in-house controls which were not of optimal quality. Some laboratories were not critical enough as to the outcome of their ICC staining results. Therefore, guidelines for hormonal determination in cytology as well as external quality control are essential.

Oestrogen and progesterone receptor; immunocytochemistry; breast carcinoma

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