Long-term prognostic impact of immunohistochemical estrogen receptor determinations compared with biochemical receptor determination in primary breast cancer

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.

Assessing the expression of two genes simultaneously in surgical specimens using polymerase chain reaction

We developed a novel polymerase chain reaction (PCR)-based method to analyze simultaneously the relative expression of two genes in a single PCR reaction. The method, relational PCR (R-PCR), utilizes special PCR primers that enable a PCR reaction to be converted from a standard uniplex reaction to a multiplex reaction in which all products are dependent on the same reaction components for amplification. We show that the quantitative ability of R-PCR is unaffected by sample nucleic acid input concentration over a range of 25-fold (30 to 750 ng of total RNA) and demonstrate excellent interexperimental reproducibility. We used R-PCR to analyze estrogen receptor gene expression in a series of invasive breast carcinomas, and our results show an excellent correlation between estrogen receptor mRNA expression and protein product accumulation determined by standard immunocytochemistry on paraffin sections.