The average probe values used by ASPIRE version 2 were (RMA signal estimates from Expression Console 1.1). All exon (PSR) and junction (JUC) probe values were analysed by the second and third step of ASPIRE version 2. The median value of background probes with the same GC content was subtracted from each probe value. Probe values with high variability and weak signal were removed from analysis before calculating the median value of all probes within a probeset.