title: Decentral gene expression analysis for ER+/Her2- breast cancer: results of a proficiency testing program for the EndoPredict assay.
abstract: Gene expression profiles provide important information about the biology of breast tumors and can be used to develop prognostic tests. However, the implementation of quantitative RNA-based testing in routine molecular pathology has not been accomplished, so far. The EndoPredict assay has recently been described as a quantitative RT-PCR-based multigene expression test to identify a subgroup of hormone-receptor-positive tumors that have an excellent prognosis with endocrine therapy only. To transfer this test from bench to bedside, it is essential to evaluate the test-performance in a multicenter setting in different molecular pathology laboratories. In this study, we have evaluated the EndoPredict (EP) assay in seven different molecular pathology laboratories in Germany, Austria, and Switzerland. A set of ten formalin-fixed paraffin-embedded tumors was tested in the different labs, and the variance and accuracy of the EndoPredict assays were determined using predefined reference values. Extraction of a sufficient amount of RNA and generation of a valid EP score was possible for all 70 study samples (100%). The EP scores measured by the individual participants showed an excellent correlation with the reference values, respectively, as reflected by Pearson correlation coefficients ranging from 0.987 to 0.999. The Pearson correlation coefficient of all values compared to the reference value was 0.994. All laboratories determined EP scores for all samples differing not more than 1.0 score units from the pre-defined references. All samples were assigned to the correct EP risk group, resulting in a sensitivity and specificity of 100%, a concordance of 100%, and a kappa of 1.0. Taken together, the EndoPredict test could be successfully implemented in all seven participating laboratories and is feasible for reliable decentralized assessment of gene expression in luminal breast cancer.
authors.affiliation: Institute of Pathology, Charité Hospital, Campus Mitte, Schumannstr. 20/21, 10117 Berlin, Germany. carsten.denkert@charite.de
authors.forename: Carsten
authors.initials: C
authors.lastname: Denkert
authors.forename: Ralf
authors.initials: R
authors.lastname: Kronenwett
authors.forename: Werner
authors.initials: W
authors.lastname: Schlake
authors.forename: Kerstin
authors.initials: K
authors.lastname: Bohmann
authors.forename: Roland
authors.initials: R
authors.lastname: Penzel
authors.forename: Karsten E
authors.initials: KE
authors.lastname: Weber
authors.forename: Heinz
authors.initials: H
authors.lastname: Höfler
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lehmann
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
authors.forename: Katja
authors.initials: K
authors.lastname: Specht
authors.forename: Margaretha
authors.initials: M
authors.lastname: Rudas
authors.forename: Hans-Heinrich
authors.initials: HH
authors.lastname: Kreipe
authors.forename: Peter
authors.initials: P
authors.lastname: Schraml
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schlake
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Bago-Horvath
authors.forename: Frank
authors.initials: F
authors.lastname: Tiecke
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Varga
authors.forename: Holger
authors.initials: H
authors.lastname: Moch
authors.forename: Marcus
authors.initials: M
authors.lastname: Schmidt
authors.forename: Judith
authors.initials: J
authors.lastname: Prinzler
authors.forename: Dontscho
authors.initials: D
authors.lastname: Kerjaschki
authors.forename: Bruno Valentin
authors.initials: BV
authors.lastname: Sinn
authors.forename: Berit Maria
authors.initials: BM
authors.lastname: Müller
authors.forename: Martin
authors.initials: M
authors.lastname: Filipits
authors.forename: Christoph
authors.initials: C
authors.lastname: Petry
authors.forename: Manfred
authors.initials: M
authors.lastname: Dietel
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics*; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D006801:Humans; D016612:Paraffin Embedding; D057089:Pathology, Molecular / Q000379:methods; D012313:RNA / Q000302:isolation & purification; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics; D011960:Receptors, Estrogen / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016707:Tissue Fixation
chemical_list: D014408:Biomarkers, Tumor; D012313:RNA; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen