title: Non-negative matrix factorization of gene expression profiles: a plug-in for BRB-ArrayTools.
abstract: CONCLUSIONS
  Non-negative matrix factorization (NMF) is an increasingly used algorithm for the analysis of complex high-dimensional data. BRB-ArrayTools is a widely used software system for the analysis of gene expression data with almost 9000 registered users in over 65 countries. We have developed a NMF analysis plug-in in BRB-ArrayTools for unsupervised sample clustering of microarray gene expression data. Our analysis tool also incorporates an algorithm for Semi-NMF which can handle both positive and negative elements for log-ratio data. Output includes a heat map of sample clusters and differentially expressed genes with extensive biological annotation. For comparison, output also includes the results of K-means clustering.
  
  
  BACKGROUND
  The NMF analysis plug-in is freely available in BRB-ArrayTools for non-commercial users. BRB-ArrayTools can be downloaded at http://linus.nci.nih.gov/BRB-ArrayTools.html. The algorithms used for NMF and Semi-NMF are available at ftp://linus.nci.nih.gov/pub/NMF.
authors.affiliation: Department of Biochemistry and Molecular Biology, Georgetown University School of Medicine, 3900 Reservoir Rd. NW, Washington, DC 20057-1455, USA.
authors.forename: Qihao
authors.initials: Q
authors.lastname: Qi
authors.forename: Yingdong
authors.initials: Y
authors.lastname: Zhao
authors.forename: MingChung
authors.initials: M
authors.lastname: Li
authors.forename: Richard
authors.initials: R
authors.lastname: Simon
mesh_terms: D000465:Algorithms; D016000:Cluster Analysis; D003196:Computer Graphics; D030541:Databases, Genetic; D020869:Gene Expression Profiling / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012984:Software