title: Transcriptome profiling of whole blood cells identifies PLEK2 and C1QB in human melanoma.
abstract: BACKGROUND
  Developing analytical methodologies to identify biomarkers in easily accessible body fluids is highly valuable for the early diagnosis and management of cancer patients. Peripheral whole blood is a "nucleic acid-rich" and "inflammatory cell-rich" information reservoir and represents systemic processes altered by the presence of cancer cells.
  
  
  RESULTS
  We conducted transcriptome profiling of whole blood cells from melanoma patients. To overcome challenges associated with blood-based transcriptome analysis, we used a PAXgene™ tube and NuGEN Ovation™ globin reduction system. The combined use of these systems in microarray resulted in the identification of 78 unique genes differentially expressed in the blood of melanoma patients. Of these, 68 genes were further analyzed by quantitative reverse transcriptase PCR using blood samples from 45 newly diagnosed melanoma patients (stage I to IV) and 50 healthy control individuals. Thirty-nine genes were verified to be differentially expressed in blood samples from melanoma patients. A stepwise logit analysis selected eighteen 2-gene signatures that distinguish melanoma from healthy controls. Of these, a 2-gene signature consisting of PLEK2 and C1QB led to the best result that correctly classified 93.3% melanoma patients and 90% healthy controls. Both genes were upregulated in blood samples of melanoma patients from all stages. Further analysis using blood fractionation showed that CD45(-) and CD45(+) populations were responsible for the altered expression levels of PLEK2 and C1QB, respectively.
  
  
  CONCLUSIONS
  The current study provides the first analysis of whole blood-based transcriptome biomarkers for malignant melanoma. The expression of PLEK2, the strongest gene to classify melanoma patients, in CD45(-) subsets illustrates the importance of analyzing whole blood cells for biomarker studies. The study suggests that transcriptome profiling of blood cells could be used for both early detection of melanoma and monitoring of patients for residual disease.
authors.affiliation: Department of Dermatology, University of Colorado Denver, Aurora, Colorado, United States of America.
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Luo
authors.forename: Steven
authors.initials: S
authors.lastname: Robinson
authors.forename: Junichi
authors.initials: J
authors.lastname: Fujita
authors.forename: Lisa
authors.initials: L
authors.lastname: Siconolfi
authors.forename: Jay
authors.initials: J
authors.lastname: Magidson
authors.forename: Carl K
authors.initials: CK
authors.lastname: Edwards
authors.forename: Karl
authors.initials: K
authors.lastname: Wassmann
authors.forename: Kathleen
authors.initials: K
authors.lastname: Storm
authors.forename: David A
authors.initials: DA
authors.lastname: Norris
authors.forename: Danute
authors.initials: D
authors.lastname: Bankaitis-Davis
authors.forename: William A
authors.initials: WA
authors.lastname: Robinson
authors.forename: Mayumi
authors.initials: M
authors.lastname: Fujita
mesh_terms: D001483:Base Sequence; D016022:Case-Control Studies; D015922:Complement C1q / Q000235:genetics*; D017931:DNA Primers; D020869:Gene Expression Profiling; D006801:Humans; D008545:Melanoma / Q000097:blood / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D008565:Membrane Proteins; C120651:PLEK2 protein, human; D015922:Complement C1q