title: MYC quantitation in cell-free plasma DNA by real-time PCR for gastric cancer diagnosis.
abstract: BACKGROUND
  Detection of tumor-associated genetic alterations in plasma of cancer patients has recently been suggested to be an accurate method for detecting early or recurrent cancer.
  
  
  METHODS
  We performed quantitative real-time PCR for MYC and GAPDH in tissue and plasma samples of 57 patients with gastric cancer and in plasma of 79 cancer-free individuals. We also performed two-color MYC fluorescence in situ hybridization (FISH) in tissue from the 57 patients with gastric cancer.
  
  
  RESULTS
  The tissue MYC/GAPDH ratio by real-time PCR was significantly correlated with MYC status by FISH (p<0.001). The mean ratio of plasma MYC/GAPDH was 5.226+/-3.578 (range: 1.25-18.35) in gastric cancer patients, and 2.436+/-0.881 (range: 1.00-5.00) in the healthy volunteers (p<0.001). We used receiver-operating characteristics (ROC) curve analysis to select two optimal plasma MYC/GAPDH cut-offs of 2.725 and 5.225. The sensitivity and specificity were 75.4% and 76.9% at 2.725, 38.6% and 100% at 5.225, respectively. The plasma MYC/GAPDH ratio from cancer patients was significantly correlated with the tissue MYC/GAPDH ratio (p=0.009), and tissue MYC status by FISH (p=0.024).
  
  
  CONCLUSIONS
  These findings suggest that the plasma MYC/GAPDH ratio, as determined by real-time PCR, may be an alternative non-invasive approach for detecting gastric cancer.
authors.affiliation: Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyoung Un
authors.initials: KU
authors.lastname: Park
authors.forename: Hee Eun
authors.initials: HE
authors.lastname: Lee
authors.forename: Do Joong
authors.initials: DJ
authors.lastname: Park
authors.forename: Eun Ji
authors.initials: EJ
authors.lastname: Jung
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
authors.forename: Hyung-Ho
authors.initials: HH
authors.lastname: Kim
authors.forename: Gheeyoung
authors.initials: G
authors.lastname: Choe
authors.forename: Woo Ho
authors.initials: WH
authors.lastname: Kim
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Lee
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D002466:Cell Nucleolus / Q000235:genetics; D002503:Centromere / Q000235:genetics; D004247:DNA / Q000097:blood* / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D016259:Genes, myc / Q000235:genetics*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000097:blood / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; D004247:DNA; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases