1. Mass-spectrometry-based quantitation of Her2 in gastroesophageal tumor tissue: comparison to IHC and FISH
- Author
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Daniel V.T. Catenacci, Les Henderson, David Krisman, Shu-Yuan Xiao, Todd Hembrough, Lei Zhao, Sheeno Thyparambil, Wei-Li Liao, Kathleen Bengali, Emma Whitcomb, Jamar Uzzell, Emily O'Day, Peng Xu, Adele Blackler, John Hart, Sang Mee Lee, Yung-Jue Bang, Marlene Darfler, Jon Burrows, and Fabiola Cecchi
- Subjects
Proteomics ,musculoskeletal diseases ,0301 basic medicine ,Cancer Research ,Pathology ,medicine.medical_specialty ,Receptor, ErbB-2 ,Biology ,Article ,Immunoenzyme Techniques ,03 medical and health sciences ,0302 clinical medicine ,Stomach Neoplasms ,Trastuzumab ,Biomarkers, Tumor ,medicine ,Humans ,Multiplex ,skin and connective tissue diseases ,Stomach cancer ,neoplasms ,In Situ Hybridization, Fluorescence ,Receiver operating characteristic ,medicine.diagnostic_test ,Selected reaction monitoring ,Gene Amplification ,Gastroenterology ,General Medicine ,medicine.disease ,Molecular biology ,030104 developmental biology ,Oncology ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,030220 oncology & carcinogenesis ,Immunohistochemistry ,human activities ,medicine.drug ,Fluorescence in situ hybridization - Abstract
Trastuzumab has shown a survival benefit in cases of Her2-positive gastroesophageal cancer (GEC). Immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) currently determine eligibility for trastuzumab-based therapy. However, these low-throughput assays often produce discordant or equivocal results. We developed a targeted proteomic assay based on selected reaction monitoring mass spectrometry (SRM-MS) and quantified levels (amol/μg) of Her2-SRM protein in cell lines (n = 27) and GEC tissues (n = 139). We compared Her2-SRM protein expression with IHC/FISH, seeking to determine optimal SRM protein expression cutoffs in order to identify HER2 gene amplification. After demonstrating assay development, precision, and stability, Her2-SRM protein measurement was observed to be highly concordant with the HER2/CEP17 ratio, particularly in a multivariate regression model adjusted for SRM expression of the covariates Met, Egfr, Her3, and HER2 heterogeneity, as well as their interactions (cell lines r 2 = 0.9842; FFPE r 2 = 0.7643). In GEC tissues, Her2-SRM protein was detected at any level in 71.2 % of cases. ROC curves demonstrated that Her2-SRM protein levels have a high specificity (100 %) at an upper-level cutoff of >750 amol/µg and sensitivity of 75 % at a lower-level cutoff of
- Published
- 2015