Hierarchical clustering of uncorrected and batch-corrected data from time point 0 hours: a) The uncorrected data form clusters reflecting the 7 different acquiry dates (red shades for arrays generated in 2006; blue shades for those generated in 2009; for precise definition of the individual acquiry dates see Table 2). In contrast, RA and OA are not grouped. b) The ComBat-corrected data (7 batches) form clusters reflecting the diseases (RA and OA) instead of the acquiry dates.
Kupfer et al. BMC Medical Genomics 2012 5:23 doi:10.1186/1755-8794-5-23