common protein biomarkers assessed by reverse phase protein arrays show considerable intratumoral heterogeneity in breast cancer tissues常见的蛋白质生物标志物评估通过反相蛋白数组显示相当大的瘤内异质性在乳腺癌组织.pdfVIP

Common Protein Biomarkers Assessed by Reverse Phase Protein Arrays Show Considerable Intratumoral Heterogeneity in Breast Cancer Tissues . . Katharina Malinowsky , Mithu Raychaudhuri , Theresa Buchner, Sabrina Thulke, Claudia Wolff, ¨ Heinz Hofler, Karl-Friedrich Becker, Stefanie Avril* ¨ ¨ Department of Pathology, Technische Universitat Munchen, Munich, Germany Abstract Proteins are used as prognostic and predictive biomarkers in breast cancer. However, the variability of protein expression within the same tumor is not well studied. The aim of this study was to assess intratumoral heterogeneity in protein expression levels by reverse-phase-protein-arrays (RPPA) (i) within primary breast cancers and (ii) between axillary lymph node metastases from the same patient. Protein was extracted from 106 paraffin-embedded samples from 15 large ($3 cm) primary invasive breast cancers, including different zones within the primary tumor (peripheral, intermediate, central) as well as 2–5 axillary lymph node metastases in 8 cases. Expression of 35 proteins including 15 phosphorylated proteins representing the HER2, EGFR, and uPA/PAI-1 signaling pathways was assessed using reverse-phase-protein-arrays. All 35 proteins showed considerable intratumoral heterogeneity within primary breast cancers with a mean coefficient of variation (CV) of 31% (range 22–43%). There were no significant differences between phosphorylated (CV 32%) and non- phosphorylated proteins (CV 31%) and in the extent of intratumoral heterogeneity within a defined tumor zone (CV 28%, range18–38%) or between different tumor zones (CV 24%, range 17–38%). Lymph node metastases from the sa