4q21 and 11q23
Tumors
B-ALL
biphenotypic AL
some ANLL
some treatment-related leukaemia
exceptional T-ALL
Genes involved
AF4 at 4q21
MLL at 11q23
Additional anomalies in 1/4 of cases with clonal evolution to hyperploidy
i(7q) (10%)
+X, +6, +8, +19, +21, +13, +10, +14