Using Biological Information To Increase the Sensitivity of Tests for Differential Expression in Low-Dose Ionizing Radiation Studies

• Activity Number: 506
• Type: Contributed
• Date/Time: Thursday, August 2, 2007 : 8:30 AM to 10:20 AM
• Sponsor: Biopharmaceutical Section
• Author(s): Ruixiao Lu*+ and Susanne R. Berglund and Alison Santana and Zelanna Goldberg and David Rocke
• Companies: University of California, Davis and University of California, Davis and University of California, Davis and University of California, Davis and University of California, Davis
• Keywords: microarray ; gene expression ; mRNA ; gene group ; pathway ; Gene Ontology

Abstract

Identification of differential expression of transcripts in human is complicated, partially because of differences in timing of transcriptional cascades between samples. We develop a new method to handle this by utilizing biological information in the analysis, after preprocessing of raw signals and analysis of the significant changes in single genes. First, select one or more pathways or genes groups and identify the probes on an array that correspond to the pathway or gene group. Second, for each probe, conduct a usual statistical analysis such as t-test for the difference between the treatment and control. We then test for whether in the aggregate this shows up or down-regulation. The significance of the test can be accessed by sampling genes or arrays. We illustrate the method with results from dose-response and time-course studies of low-dose radiation exposure in-vivo in humans.