Open Access Research

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

Ning Lv1,2, Xiaoming Xie1,2, Qidong Ge1,2, Suxia Lin2,3, Xi Wang1,2, Yanan Kong1,2, Hongliu Shi1,2, Xinhua Xie1,2 and Weidong Wei1,2*

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Author affiliations

1 Department of Breast Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong 510060, P. R. China

2 State Key Laboratory of Oncology in South China, Guangzhou, Guangdong 510060, P. R. China

3 Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong 510060, P. R. China

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Citation and License

Diagnostic Pathology 2011, 6:118 doi:10.1186/1746-1596-6-118

Published: 2 December 2011

Abstract

Background

The epidermal growth factor receptor (EGFR) is an available target of effective anti-EGFR therapy for human breast cancer. The aim of this study was to assess the presence of EGFR gene amplification and mutations in breast cancer and to analyze the association between the statuses of these two gene alterations.

Materials and methods

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.

Results

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).

Conclusion

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.

Virtual Slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2521111805741248 webcite

Keywords:
breast cancer; epidermal growth factor receptor, EGFR; FISH; gene amplification; gene mutation; real-time PCR.