Immune gene rearrangement profiles in pediatric and adult ALL. Pediatric patients with ALL show a higher frequency of mature immunogenotypes within both IG and TR genes, a higher number of IG/TR markers, and a higher percentage of cross-lineage TR rearrangements compared with adult patients with ALL. In contrast, older patients with ALL are characterized by a higher frequency of expanded “accompanying” T-cell clones. Figure created with BioRender.com.