A proposed approach to identify DE and DV genes in a multi-class microarray dataset using quantile regression. Genes that are DE across multiple classes of samples can be identified by checking whether the RSAD for fitting a DE model, which specifies one median value per class is much smaller than the RSAD for a simpler model (a non-DE model) which specifies only one median value for all k classes. Similarly, we can identify DV genes by checking whether the DV model with 2k parameters is much better than the non-DV model with k + 1 parameters, where k is the number of distinct classes.
Ho et al. BMC Genomics 2009 10(Suppl 3):S16 doi:10.1186/1471-2164-10-S3-S16