title: SHOX2 DNA methylation is a biomarker for the diagnosis of lung cancer in plasma.
abstract: BACKGROUND
  Recently, analysis of DNA methylation of the SHOX2 locus was shown to reliably identify lung cancer in bronchial aspirates of patients with disease. As a plasma-based assay would expand the possible applications of the SHOX2 biomarker, this study aimed to develop a modified SHOX2 assay for use in a blood-based test and to analyze the performance of this optimized SHOX2 methylation assay in plasma.
  
  
  METHODS
  Quantitative real-time polymerase chain reaction was used to analyze DNA methylation of SHOX2 in plasma samples from 411 individuals. A training study (20 stage IV patients with lung cancer and 20 controls) was performed to show the feasibility of detecting the SHOX2 biomarker in blood and to determine a methylation cutoff for patient classification. The resulting cutoff was verified in a testing study composed of 371 plasma samples from patients with lung cancer and controls.
  
  
  RESULTS
  DNA methylation of SHOX2 could be used as a biomarker to distinguish between malignant lung disease and controls at a sensitivity of 60% (95% confidence interval: 53-67%) and a specificity of 90% (95% confidence interval: 84-94%). Cancer in patients with stages II (72%), III (55%), and IV (83%) was detected at a higher sensitivity when compared with stage I patients. Small cell lung cancer (80%) and squamous cell carcinoma (63%) were detected at the highest sensitivity when compared with adenocarcinomas.
  
  
  CONCLUSIONS
  SHOX2 DNA methylation is a biomarker for detecting the presence of malignant lung disease in blood plasma from patients with lung cancer.
authors.affiliation: Theracode GmbH, Mainz, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kneip
authors.forename: Bernd
authors.initials: B
authors.lastname: Schmidt
authors.forename: Anke
authors.initials: A
authors.lastname: Seegebarth
authors.forename: Sabine
authors.initials: S
authors.lastname: Weickmann
authors.forename: Michael
authors.initials: M
authors.lastname: Fleischhacker
authors.forename: Volker
authors.initials: V
authors.lastname: Liebenberg
authors.forename: John K
authors.initials: JK
authors.lastname: Field
authors.forename: Dimo
authors.initials: D
authors.lastname: Dietrich
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D016022:Case-Control Studies; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000097:blood* / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D000074122:Short Stature Homeobox Protein; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D018398:Homeodomain Proteins; C106071:SHOX protein, human; D000074122:Short Stature Homeobox Protein