Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2003-6-12
pubmed:abstractText
MOTIVATION: An important goal in analyzing microarray data is to determine which genes are differentially expressed across two kinds of tissue samples or samples obtained under two experimental conditions. Various parametric tests, such as the two-sample t-test, have been used, but their possibly too strong parametric assumptions or large sample justifications may not hold in practice. As alternatives, a class of three nonparametric statistical methods, including the empirical Bayes method of Efron et al. (2001), the significance analysis of microarray (SAM) method of Tusher et al. (2001) and the mixture model method (MMM) of Pan et al. (2001), have been proposed. All the three methods depend on constructing a test statistic and a so-called null statistic such that the null statistic's distribution can be used to approximate the null distribution of the test statistic. However, relatively little effort has been directed toward assessment of the performance or the underlying assumptions of the methods in constructing such test and null statistics. RESULTS: We point out a problem of a current method to construct the test and null statistics, which may lead to largely inflated Type I errors (i.e. false positives). We also propose two modifications that overcome the problem. In the context of MMM, the improved performance of the modified methods is demonstrated using simulated data. In addition, our numerical results also provide evidence to support the utility and effectiveness of MMM.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1367-4803
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1046-54
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:12801864-Algorithms, pubmed-meshheading:12801864-Computer Simulation, pubmed-meshheading:12801864-Gene Expression Profiling, pubmed-meshheading:12801864-Gene Expression Regulation, Neoplastic, pubmed-meshheading:12801864-Genetic Variation, pubmed-meshheading:12801864-Humans, pubmed-meshheading:12801864-Leukemia, Myeloid, pubmed-meshheading:12801864-Models, Genetic, pubmed-meshheading:12801864-Models, Statistical, pubmed-meshheading:12801864-Oligonucleotide Array Sequence Analysis, pubmed-meshheading:12801864-Precursor Cell Lymphoblastic Leukemia-Lymphoma, pubmed-meshheading:12801864-Quality Control, pubmed-meshheading:12801864-Reproducibility of Results, pubmed-meshheading:12801864-Sensitivity and Specificity, pubmed-meshheading:12801864-Sequence Alignment, pubmed-meshheading:12801864-Sequence Analysis, DNA, pubmed-meshheading:12801864-Sequence Homology, Nucleic Acid
pubmed:year
2003
pubmed:articleTitle
Modified nonparametric approaches to detecting differentially expressed genes in replicated microarray experiments.
pubmed:affiliation
Division of Biostatistics, School of Public Health, University of Minnesota, MMC 303, A460 Mayo Building, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Evaluation Studies, Validation Studies