Should We Abandon the t-Test in the Analysis of Gene Expression Microarray Data: A Comparison of Variance Modeling Strategies

• Published in: PloS one Vol. 5; no. 9; p. e12336
• Main Authors: Jeanmougin, Marine, de Reynies, Aurelien, Marisa, Laetitia, Paccard, Caroline, Nuel, Gregory, Guedj, Mickael
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.09.2010; Public Library of Science (PLoS)
• Subjects: Analysis of Variance; Applied mathematics; Bioinformatics; Breast cancer; Cancer; Comparative analysis; Computer Simulation; Control methods; Data processing; DNA microarrays; Gene expression; Gene Expression Profiling - statistics & numerical data; Genes; Genetics and Genomics/Bioinformatics; Genetics and Genomics/Gene Expression; Genomes; Genomics; Head & neck cancer; Leukemia; Lymphoma; Mathematics; Mathematics/Statistics; Metastasis; Modelling; Models, Statistical; Molecular Biology/Bioinformatics; Oligonucleotide Array Sequence Analysis - statistics & numerical data; Power; Probability; Statistics; Student's t-test; Studies; Variance; Variance analysis; France
• DOI: 10.1371/journal.pone.0012336
• ISSN: 1932-6203

High-throughput post-genomic studies are now routinely and promisingly investigated in biological and biomedical research. The main statistical approach to select genes differentially expressed between two groups is to apply a t-test, which is subject of criticism in the literature. Numerous alternatives have been developed based on different and innovative variance modeling strategies. However, a critical issue is that selecting a different test usually leads to a different gene list. In this context and given the current tendency to apply the t-test, identifying the most efficient approach in practice remains crucial. To provide elements to answer, we conduct a comparison of eight tests representative of variance modeling strategies in gene expression data: Welch's t-test, ANOVA [1], Wilcoxon's test, SAM [2], RVM [3], limma [4], VarMixt [5] and SMVar [6]. Our comparison process relies on four steps (gene list analysis, simulations, spike-in data and re-sampling) to formulate comprehensive and robust conclusions about test performance, in terms of statistical power, false-positive rate, execution time and ease of use. Our results raise concerns about the ability of some methods to control the expected number of false positives at a desirable level. Besides, two tests (limma and VarMixt) show significant improvement compared to the t-test, in particular to deal with small sample sizes. In addition limma presents several practical advantages, so we advocate its application to analyze gene expression data.