title: Preanalytical variables and performance of diagnostic RNA-based gene expression analysis in breast cancer.
abstract: Prognostic multigene expression assays have become widely available to provide additional information to standard clinical parameters and to support clinicians in treatment decisions. In this study, we analyzed the impact of variations in tissue handling on the diagnostic EndoPredict test results. EndoPredict is a quantitative reverse transcription PCR assay conducted on RNA from formalin-fixed, paraffin-embedded (FFPE) tissue that predicts the likelihood of distant recurrence in patients with ER-positive/HER2-negative breast cancer. In this study, we performed a total of 138 EndoPredict assays to study the effects of preanalytical variables such as time to fixation, fixation time, tumor cell content, and section storage time on the EndoPredict test results. A time to fixation of up to 12 h and fixation of up to 5 days did not affect the results of the gene expression test. Paired samples of FFPE sections with tumor cell content ranging from 15 to 95 % and tumor-enriched samples showed a correlation coefficient of 0.97. Test results of tissue sections that have been stored for 12 months at +4 or +20 °C showed a correlation of 0.99 when compared to results of nonstored sections. In conclusion, preanalytical tissue handling is not a critical factor for diagnostic gene expression analysis with the EndoPredict assay. The test can therefore be easily integrated into the standard workflow of molecular pathology.
authors.affiliation: Institute of Pathology Munich-North, Ernst-Platz-Straße 2, 80992, Munich, Germany, poremba@pathologie-muenchen.de.
authors.forename: Christopher
authors.initials: C
authors.lastname: Poremba
authors.forename: Jennifer
authors.initials: J
authors.lastname: Uhlendorff
authors.forename: Berit M
authors.initials: BM
authors.lastname: Pfitzner
authors.forename: Guido
authors.initials: G
authors.lastname: Hennig
authors.forename: Kerstin
authors.initials: K
authors.lastname: Bohmann
authors.forename: Hans
authors.initials: H
authors.lastname: Bojar
authors.forename: Veit
authors.initials: V
authors.lastname: Krenn
authors.forename: Jan C
authors.initials: JC
authors.lastname: Brase
authors.forename: Franziska
authors.initials: F
authors.lastname: Haufe
authors.forename: Manuela
authors.initials: M
authors.lastname: Averdick
authors.forename: Manfred
authors.initials: M
authors.lastname: Dietel
authors.forename: Ralf
authors.initials: R
authors.lastname: Kronenwett
authors.forename: Carsten
authors.initials: C
authors.lastname: Denkert
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016612:Paraffin Embedding; D057089:Pathology, Molecular / Q000379:methods*; D012313:RNA / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D013048:Specimen Handling; D013997:Time Factors; D016707:Tissue Fixation
chemical_list: D012313:RNA