HER-2 assessment in formalin-fixed paraffin-embedded breast cancer tissue by well-based reverse phase protein array |
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Authors: | Candice Perry Catherine M Conway Jeong Won Ha Till Braunschweig Jennifer Morris Kris Ylaya Hanbyoul Cho Joon-Yong Chung Stephen M Hewitt |
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Affiliation: | .Tissue Array Research Program, Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA ;.Institute of Pathology, RWTH Aachen University, Aachen, Germany ;.Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, 425-707 Korea ;.Antibody Characterization Laboratory, Advanced Technology Program, Leidos Biomedical Research, Inc, Frederick, MD USA |
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Abstract: | BackgroundThe human epidermal growth factor receptor-2 (HER-2) expression level is a critical element for determining the prognosis and management of breast cancer. HER-2 targeted therapy in breast cancer depends on the reliable assessment of HER-2 expression status but current standard methods are lacking a rigorous quantitative assay. To address this challenge, we developed an assessment of HER-2 expression method by well-based reverse phase protein array (RPPA).ResultsWell-based RPPA is based on a robust protein isolation methodology paired with a novel electrochemiluminescence detection system. HER-2 value of well-based RPPA significantly correlated with dot blotting results (R2 = 0.939). By well-based RPPA, we successfully detected HER-2 expression in 76 human breast formalin-fixed paraffin-embedded tissue samples. We observed 93.4% (71/76) concordance between well-based RPPA and current HER-2 immunohistochemical assessment guideline. When the cutoff level of HER-2 value was set to 0.689 (HER-2/GAPDH) on the basis of receiver-operating characteristic curve, the area under the curve was 0.975 (95% CI, 0.941-1.000). Sensitivity and specificity of well-based RPPA was 92.1% and 94.7%, respectively.ConclusionsHER-2 value by well-based RPPA was correlated with the current HER-2 status guideline, suggesting that this normalized HER-2 assessment may offer advantages over unnormalized current immunohistochemical assessment methods. |
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Keywords: | Breast cancer Formalin-fixed paraffin-embedded Human epidermal growth factor receptor- 2 Immunohistochemistry Reverse-phase protein array |
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