Epidermal growth factor receptor in breast carcinoma: association between gene copy number and mutations

EGFR gene amplification and mutations were investigated in formalin-fixed, paraffin-embedded tissues from 139 Chinese female patients with breast cancer by means of fluorescence in-situ hybridization (FISH) and fluorescently labeled real-time quantitative polymerase chain reaction (RT-PCR), respectively.EGFR gene amplification was observed in 46/139 (33.1%) of cases by FISH. Based on RT-PCR, 2/139 (1.4%) samples had EGFR gene mutations. Overall, only 1 (0.7%) of the cases was identified with both whole gene amplification and mutation, and 92 (66.2%) of cases were negative for both. High gene copy numbers of EGFR had significant correlation with the occurrence of EGFR protein expressions (P = 0.002).In this study, EGFR mutations were presented in only two samples, indicating that EGFR mutations should not be employed in future trials with anti-EGFR therapies for breast cancer. However, EGFR whole gene amplification is frequently observed in patients with breast cancer. It will be of significant interest to investigate whether EGFR gene copy number is a suitable screening test for EGFR-targeted therapy for breast cancer.The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2521111805741248 webciteThe human epidermal growth factor receptor (HER/EGFR/ErbB) family of receptor tyrosine kinases is comprised of four transmembrane growth factor receptor proteins that share similarities in structure and function. The epidermal growth factor receptor (HER-1/EGFR/ErbB1), encoded by the gene located on the short arm of chromosome 7, is a member of this family of Type I transmembrane tyrosine kinase receptors. EGFR is a 170 kDa transmembrane protein consisting of an intracellular domain (tyrosine kinase domain), a short transmembrane and juxtamembrane domain, and an extracellular domain (ligand-binding domain) with ligand-activated tyrosine kinase activity [1]. EGFR can be activated by various growth factor ligands, including epiderm