Comparative expression profiling strategy and general work flow. (A) The principle of comparative expression profiling exemplified by evaluating candidate genes (ie, genes regulated in the majority of childhood ALL samples) in additional GC-sensitive and GC-resistant systems. Coregulation in the former supports, whereas coregulation in the latter argues against, a potential role of a candidate gene in the death response. Other relevant information, such as interspecies conservation, de novo protein biosynthesis-dependence, etc, can also be derived by comparisons with the additional systems as outlined in Table 1. (B) Summary of workflow described in “Introduction.” The complete databases are available at www.ncbi.nlm.nih.gov/geo/ (GEO accession numbers: GSE2677, GSE2842, GSE2843). Tables corresponding to various database subsets are shown in the Supplemental Materials, as indicated. The final 22 genes are presented in Table 5. The additional systems comprising database 2 and their use for evaluating the possible significance of the candidate genes in the death response are explained in Table 1.