Distribution of cytogenetic abnormalities from data collected from UK childhood ALL treatment trials. (A) Relative incidence of the established cytogenetic abnormalities among childhood BCP-ALL. (B) Distribution of different cytogenetic subgroups according to age. The abnormalities are color coded and the incidence of each abnormality indicated according to age group. The relative incidence of T-ALL is also shown. IGH@ indicates all translocations except with CRLF2; CRLF2, IGH@-CRLF2 and P2RY8-CRLF2; hap/hypo, hypodiploidy (< 44 chromosomes); t(9;22), BCR-ABL1 positive; and HeH, high hyperdiploidy.