Quantum dot-based quantitative immunofluorescence detection and spectrum analysis of epidermal growth factor receptor in breast cancer tissue arrays

Xue-Qin Yang^1,2, Chuang Chen¹, Chun-Wei Peng¹, Jin-Xuan Hou¹, Shao-Ping Liu¹, Chu-Bo Qi³, Yi-Ping Gong⁴, Xiao-Bo Zhu⁵, Dai-Wen Pang⁶, Yan Li^1
1Department of Oncology, Zhongnan Hospital of Wuhan University, Hubei Key Laboratory on Tumor Biological Behaviors and Hubei Cancer Clinical Study Center, Wuhan; ²Medical School of Jingchu University of Technology, Jingmen; ³Department of Pathology; ⁴Department of Breast Surgery, Hubei Cancer Hospital, Wuhan; ⁵Wuhan Jiayuan Quantum Dots Co Ltd and Wuhan Tumor Nanometer Diagnosis Engineering Research Center, Wuhan; ⁶Key Laboratory of Analytical Chemistry for Biology and Medicine, College of Chemistry and Molecular Sciences, and State Key Laboratory of Virology, Wuhan University, Wuhan, People's Republic of China

Background: The epidermal growth factor receptor (EGFR) is a promising therapeutic target in cancer, but its clinical value in breast cancer remains controversial. Our previous studies have found that quantitative analysis of biomarkers with quantum dot-based nanotechnology had better detection performance than conventional immunohistochemistry. The present study was undertaken to investigate the prognostic value of EGFR in breast cancer using quantum dot-based quantitative spectral analysis.
Methods: EGFR expression in 65 breast cancer specimens was detected by immunohistochemistry and quantum dot-immunohistochemistry, and comparisons were made between the two methods. EGFR expression in tissue microarrays of 240 breast cancer patients was then detected by quantum dot-immunohistochemistry and spectral analysis. The prognostic value of EGFR immunofluorescence area (EGFR area) for five-year recurrence-free survival was investigated.
Results: The same antigen localization, high correlation of staining rates (r = 0.914), and high agreement of measurement (κ= 0.848) of EGFR expression in breast cancer were found by quantum dot-immunohistochemistry and immunohistochemistry. The EGFR area showed significant differences by tumor grade, lymph node status, HER2 status, and hormone receptor status (all P < 0.05). Patients in the large EGFR area (≥30.51) group had a significantly higher five-year recurrence rate (47.2% versus 27.4%, P = 0.002) and worse five-year recurrence-free survival (log-rank test, P = 0.0015) than those in the small EGFR area (<30.51) group. In the subgroups, EGFR area was an independent prognosticator in the HER2-positive and lymph node-positive subgroups.
Conclusion: Quantum dot-based quantitative detection demonstrates the prognostic value of EGFR area in the HER2-positive and lymph node-positive subgroups of invasive breast cancer.

Keywords: quantum dots, breast cancer, epidermal growth factor receptor, quantitative analysis, recurrence-free survival, prognosis