Allelokaryotyping of pediatric ALL. (A) Genetic clustering of 393 ALL samples. Genetic status of each chromosomal region is visualized. Vertical axis: chromosomes, p: short arms, q: long arms. Horizontal axis: individual cases. CN: copy number of alleles. UPD: uniparental disomy. Locations of PBX1, INK4A/ARF(p16), and ETV6 genes are indicated. A rectangle indicates cases having 9p and 20q deletions. (B) Three common genomic abnormalities detected in ALL by SNP-chip analysis. Left panel: Deletion of 9p is frequently detected; the arrow indicates the commonly deleted region (CDR) where the p16INK4A gene is located. Right panel: Deletion of 12p often occurs. The arrow indicates that the CDR is where the ETV6 gene is localized. Green lines under the chromosome indicate the deleted regions in individual cases. Brown lines above the chromosome indicate the duplicated regions. Only representative cases are shown. Green and red bands on idiograms indicate centromeres and noncoding regions, respectively. Bottom panel: Venue diagram of 3 common abnormalities detected in this study. Numbers of respective cases in each category are indicated. HD: ALL with hyperdiploid (chromosomes > 50). ETV6Del: ALL with deletion of ETV6 gene. p16Del: ALL with deletion of p16INK4A gene.