Immunohistochemistry on cell blocks from fine-needle cytopunctures of primary breast carcinomas and lymph node metastases

We assessed the reliability of prognostic biologic markers by means of immunohistochemistry on cell blocks obtained from diagnostic fine-needle cytopunctures of breast carcinomas and their lymph node metastases. Immunohistochemical studies of MIB-1 (Ki-67), estrogen receptors (ER), progesterone receptors (PR), p53, and c-erb-B-2 were performed in 55 cases of primary breast carcinoma on cell blocks (cytoblock technique) and on their corresponding tissue samples (46 mastectomy specimens and 9 Trucut biopsies) and in 38 cases on cell blocks from fine-needle cytopunctures of both the primary breast tumors and their concurrent lymph node metastases. Interobserver reproducibility ranged from 87 to 100%, depending on the marker. A good correlation was observed between immunostaining assessment on cell blocks and on the corresponding tumor tissues as follows: Ki-67 (85%), ER (96%), PR (82%), p53 (76%), and c-erb-B-2 (84%). An excellent correlation was observed between cell-block results for primary tumors and node metastases; however, a far higher percentage of Ki-67-positive nuclei was observed in the nodes than in the corresponding tumors in seven cases. All nodes corresponding to ER- or PR-negative tumors were also negative, whereas the nodes corresponding to two ER-positive and one PR-positive tumor were negative. Marked discrepancies were also noted with p53 in two cases and with c-erb-B-2 in two cases. Most discrepancies occurred with Trucut biopsies and with breast tumors that contained a large intraductal component. We conclude that cell blocks prepared from fine-needle cytopuncture specimens of breast carcinomas and their node metastases are useful when planning neoadjuvant treatment.