A comparative assessment of HER2 status in operable breast cancer by real-time RT-PCR and by immunohistochemistry Piotr Potemski 1 ABCDEFG, Elżbieta Płuciennik 2,3 BC, Andrzej K. Bednarek 3 ABCDG, Renata Kusińska 2 BF, Grażyna Pasz-Walczak 2 B, Dorota Jesionek-Kupnicka 2 B, Cezary Watała 4 C, Radzisław Kordek 2 ABDEG 1 Department of Chemotherapy, Medical University of Łódź, Copernicus Memorial Hospital, Łódź, Poland 2 Department of Pathology, Medical University of Łódź, Copernicus Memorial Hospital, Łódź, Poland 3 Department of Molecular Cancerogenesis, Medical University of Łódź, Łódź, Poland 4 Department of Hemostatic Disorders, Medical University of Łódź, Łódź, Poland Source of support: A grant from the Medical University in Łódź, Poland (No. 502-11-285), and grants from the Polish National Committee of Scientific Research (KBN, Warsaw, Poland; No. 2 PO5E 099/28 and No. 3 PO5A 113/23) Summary Background: The most commonly used methods for detecting HER2 gene amplification in breast cancer are immunohistochemistry and fluorescence in-situ hybridization. The aim of this retrospective study was to assess HER2 expression by real-time RT-PCR. Material/Methods: Expression of HER2 was analyzed by real-time RT-PCR and immunohistochemistry in specimens of invasive ductal breast cancer tissue obtained from 131 women during radical mastectomy. Results: There was a highly significant difference in mean relative gene expression between HER2-positive and HER2-negative patients as assessed by immunostaining (22.10±41.89 vs. 3.17±8.76; p<0.001). With a median follow-up of 56 months, the cancer-specific survival of HER2-positive patients as- sessed by RT-PCR was worse in all cases and in the node-positive group. In multivariate analysis, HER2 status was an independent prognostic factor in all patients. Conclusions: Real-time RT-PCR is a valuable method for determining HER2 status, but the selection of the cut- off point of the relative gene expression differentiating between HER2-negative and -positive tu- mors is essential. key words: HER2 • real-time RT-PCR • immunohistochemistry • breast cancer Full-text PDF: http://www.medscimonit.com/fulltxt.php?IDMAN=9653 Word count: 2210 Tables: 5 Figures: — References: 16 Author’s address: Dr. Piotr Potemski, Department of Chemotherapy, Medical University of Łódź, Copernicus Memorial Hospital, Paderewski 4 Str., 93-509 Łódź, Poland; e-mail: piotrpo@mp.pl Authors’ Contribution: A Study Design B Data Collection C Statistical Analysis D Data Interpretation E Manuscript Preparation F Literature Search G Funds Collection Received: 2006.09.05 Accepted: 2006.11.03 Published: 2006.12.01 MT57 Diagnostics and Medical Technology WWW. MEDSCIMONIT.COM © Med Sci Monit, 2006; 12(12): MT57-61 PMID: 17136015 MT Current Contents/Clinical Medicine • SCI Expanded • ISI Alerting System • Index Medicus/MEDLINE • EMBASE/Excerpta Medica • Chemical Abstracts • Index Copernicus