Cytogenetics, FISH, and SNP 6.0 profile of EBF1-PDGFRB–positive patients. (A) Karyogram from the diagnostic bone marrow of patient 6 showing that both copies of chromosome 5 are abnormal, suggesting the presence of balanced translocation t(5;5)(q33.1;q33.3) (lower arrows). The karyogram also shows a deletion of the short arm of chromosome 9 (upper arrow). (B) FISH using the EBF1 break-apart probe (described in supplemental Figure 3B) showing a balanced rearrangement (patient 6) and (C) showing an unbalanced rearrangement consistent with the 5q33 deletion (patient 7). (D) SNP 6.0 profile of chromosome 5 in patient 3, showing a series of deletions along the long arm of chromosome 5 consistent with complex rearrangements, such as chromothripsis. This profile was conserved between diagnosis and relapse.