title: Regularized gene selection in cancer microarray meta-analysis.
abstract: BACKGROUND
  In cancer studies, it is common that multiple microarray experiments are conducted to measure the same clinical outcome and expressions of the same set of genes. An important goal of such experiments is to identify a subset of genes that can potentially serve as predictive markers for cancer development and progression. Analyses of individual experiments may lead to unreliable gene selection results because of the small sample sizes. Meta analysis can be used to pool multiple experiments, increase statistical power, and achieve more reliable gene selection. The meta analysis of cancer microarray data is challenging because of the high dimensionality of gene expressions and the differences in experimental settings amongst different experiments.
  
  
  RESULTS
  We propose a Meta Threshold Gradient Descent Regularization (MTGDR) approach for gene selection in the meta analysis of cancer microarray data. The MTGDR has many advantages over existing approaches. It allows different experiments to have different experimental settings. It can account for the joint effects of multiple genes on cancer, and it can select the same set of cancer-associated genes across multiple experiments. Simulation studies and analyses of multiple pancreatic and liver cancer experiments demonstrate the superior performance of the MTGDR.
  
  
  CONCLUSIONS
  The MTGDR provides an effective way of analyzing multiple cancer microarray studies and selecting reliable cancer-associated genes.
authors.affiliation: Department of Epidemiology and Public Health, Yale University, New Haven, CT 06520, USA. shuangge.ma@yale.edu
authors.forename: Shuangge
authors.initials: S
authors.lastname: Ma
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
mesh_terms: D000465:Algorithms; D001499:Bayes Theorem; D014408:Biomarkers, Tumor; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism; D008297:Male; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor