title: Getting the right cells to the array: Gene expression microarray analysis of cell mixtures and sorted cells.
abstract: BACKGROUND
  Most biological samples are cell mixtures. Some basic questions are still unanswered about analyzing these heterogeneous samples using gene expression microarray technology (MAT). How meaningful is a cell mixture's overall gene expression profile (GEP)? Is it necessary to purify the cells of interest before microarray analysis, and how much purity is needed? How much does the purification itself distort the GEP, and how well can the GEP of a small cell subset be recovered?
  
  
  METHODS
  Model cell mixtures with different cell ratios were analyzed by both spotted and Affymetrix MAT. GEP distortion during cell purification and GEPs of purified cells were studied. CD34+ cord blood cells were purified and analyzed by MAT.
  
  
  RESULTS
  GEPs for mixed cell populations were found to mirror the cell ratios in the mixture. Over 75% pure samples were indistinguishable from pure cells by their overall GEP. Cell purification preserved the GEP. The GEPs of small cell subsets could be accurately recovered by cell sorting both from model cell mixtures and from cord blood.
  
  
  CONCLUSIONS
  Purification of small cell subsets from a mixture prior to MAT is necessary for meaningful results. Even completely hidden GEPs of small cell subpopulations can be recovered by cell sorting.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, 77555, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Szaniszlo
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Mala
authors.initials: M
authors.lastname: Sinha
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Reece
authors.forename: James W
authors.initials: JW
authors.lastname: Van Hook
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Luxon
authors.forename: James F
authors.initials: JF
authors.lastname: Leary
mesh_terms: D001773:Blood Cells; D002460:Cell Line; D002469:Cell Separation / Q000379:methods*; D002477:Cells; D005434:Flow Cytometry / Q000379:methods; D020869:Gene Expression Profiling; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*