title: Centralization: a new method for the normalization of gene expression data.
abstract: Microarrays measure values that are approximately proportional to the numbers of copies of different mRNA molecules in samples. Due to technical difficulties, the constant of proportionality between the measured intensities and the numbers of mRNA copies per cell is unknown and may vary for different arrays. Usually, the data are normalized (i.e., array-wise multiplied by appropriate factors) in order to compensate for this effect and to enable informative comparisons between different experiments. Centralization is a new two-step method for the computation of such normalization factors that is both biologically better motivated and more robust than standard approaches. First, for each pair of arrays the quotient of the constants of proportionality is estimated. Second, from the resulting matrix of pairwise quotients an optimally consistent scaling of the samples is computed.
authors.affiliation: SCAI - Institute for Algorithms and Scientific Computing, GMD - German National Research Center for Information Technology, Schloss Birlinghoven, Sankt Augustin, 53754, Germany. Alexander.Zien@gmd.de
authors.forename: A
authors.initials: A
authors.lastname: Zien
authors.forename: T
authors.initials: T
authors.lastname: Aigner
authors.forename: R
authors.initials: R
authors.lastname: Zimmer
authors.forename: T
authors.initials: T
authors.lastname: Lengauer
mesh_terms: D019295:Computational Biology; D020869:Gene Expression Profiling / Q000706:statistics & numerical data*; D005821:Genetic Techniques / Q000706:statistics & numerical data; D008957:Models, Genetic; D020411:Oligonucleotide Array Sequence Analysis / Q000706:statistics & numerical data*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger