The (4;11) translocation in acute leukaemia of childhood: the importance of additional chromosomal aberrations.

Case reports of four girls and one boy with acute lymphoblastic leukaemia (ALL) or acute myeloid leukaemia (AML) and t(4;11) are presented. The incidence of t(4;11) ascertained at diagnosis in ALL was 2.6% and in AML 5.3%. Four of the children were under 2 years and one was 11 years at diagnosis. Leucocyte counts above 71 X 10(9)/l and liver, spleen and node enlargement were found in all cases. Blasts of the four cases tested at diagnosis were negative to the c-ALL antigen and either TdT+ (ALL) or TdT- (AML M1). Maximum survival was less than 8 months. Additional chromosomal change was found at diagnosis in two cases and in relapse in a third. In the case of AML t(4;11) (q21;p15) was present as a second translocation. Additional numerical changes, in these and other reported cases, included + 6, commonly found in ALL, +8, +19, more often reported in AML. It is suggested that additional chromosomal changes in these cases support cytochemical and surface marker evidence that t(4;11) has a pluripotent target cell, similar to that of the Philadelphia translocation.