title: Four-gene expression ratio test for survival in patients undergoing surgery for mesothelioma.
abstract: BACKGROUND
  Malignant pleural mesothelioma has few effective treatments, one being cytoreductive surgery. We previously developed a gene ratio test to predict outcome of malignant pleural mesothelioma patients undergoing surgery. In this study, we investigated the predictive value and technical assay performance of this test in patients with malignant pleural mesothelioma.
  
  
  METHODS
  Clinical data were obtained prospectively from 120 consecutive patients with malignant pleural mesothelioma who were scheduled for debulking surgery at one institution. Specimens were obtained at surgery or by pleural biopsy examination. Expression data for four genes were collected from tumor specimens, and three ratios of gene expression (TM4SF1/PKM2, TM4SF1/ARHGDIA, and COBLL1/ARHGDIA) were determined by quantitative reverse transcriptase-polymerase chain reaction. Patients were assigned to good or poor outcome groups by the gene ratio test. Survival was estimated by the Kaplan-Meier method and the log-rank test in univariate analyses. A multivariable Cox proportional hazards model was used to control for prognostic factors. Technical robustness was determined by using up to 30 specimens per patient, two biopsy techniques, and two performance sites. All statistical tests were two-sided.
  
  
  RESULTS
  The test predicted overall survival (P < .001) and cancer-specific survival (P = .007) in univariate analysis and overall survival in multivariable analysis (hazard ratio for death = 2.09, 95% confidence interval [CI] = 1.27 to 3.45, P = .004). The test was reproducible within patients and repeatable between two determinations for specimens with widely varying tumor cell contents. Repeatability between two determinations was 88.5% (95% CI = 84.0% to 92.2%) or, when technically unacceptable test values were excluded, 91.9% (95% CI = 87.4% to 95.1%). Reproducibility between two determinations was 96.1% (95% CI = 86.5% to 99.5%). Combining the gene ratio test and other prognostic factors allowed prospective discrimination between patients at high risk (median survival = 6.9 months, 95% CI = 2.6 to 8.9 months; 3-year survival = 0%) and low risk (median survival = 31.9 months, 95% CI = 21.9 to 41.7 months; 3-year survival = 42%).
  
  
  CONCLUSIONS
  The gene ratio test for survival of patients with malignant pleural mesothelioma has robust predictive value and technical assay performance.
authors.affiliation: Department of Surgery, Division of Thoracic Surgery, Harvard Medical School and Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Gordon
authors.forename: Lingsheng
authors.initials: L
authors.lastname: Dong
authors.forename: Beow Y
authors.initials: BY
authors.lastname: Yeap
authors.forename: William G
authors.initials: WG
authors.lastname: Richards
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Glickman
authors.forename: Heather
authors.initials: H
authors.lastname: Edenfield
authors.forename: Madhubalan
authors.initials: M
authors.lastname: Mani
authors.forename: Richard
authors.initials: R
authors.lastname: Colquitt
authors.forename: Gautam
authors.initials: G
authors.lastname: Maulik
authors.forename: Branden
authors.initials: B
authors.lastname: Van Oss
authors.forename: David J
authors.initials: DJ
authors.lastname: Sugarbaker
authors.forename: Raphael
authors.initials: R
authors.lastname: Bueno
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000954:Antigens, Surface / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008654:Mesothelioma / Q000737:chemistry* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009367:Neoplasm Staging; D016017:Odds Ratio; D020411:Oligonucleotide Array Sequence Analysis; D010997:Pleural Neoplasms / Q000737:chemistry* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011770:Pyruvate Kinase / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C074075:TM4SF1 protein, human; D011770:Pyruvate Kinase