Dmitry N Grigoryev1, Shwu-Fan Ma1, Rafael A Irizarry2, Shui Qing Ye3, John Quackenbush4 and Joe GN Garcia5 
1
Center for Translational Respiratory Medicine, Gene Expression Profiling Core, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Hopkins Bayview Circle, Baltimore, MD 21224, USA
2
Department of Biostatistics, Johns Hopkins University, Baltimore, MD 21205, USA
3
Center for Translational Respiratory Medicine, Johns Hopkins University, Eastern Ave, Baltimore, MD 21224, USA
4
The Institute for Genomic Research, Medical Center Drive, Rockville, MD 20850, USA
5
Center for Translational Respiratory Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, East Monument Street, Baltimore, MD 21287, USA