The t(4;11)-positive acute lymphoblastic leukemia (ALL) is a rare disease in children above the age of 1 year. We studied the clinical and biological characteristics in 32 consecutively diagnosed childhood cases (median age 10.0 years, range 1.0-17.1 years). Immunophenotyping revealed a pro-B and a pre-B stage in 24 and eight cases, respectively. IGH genes were rearranged in 84% of leukemias with a predominance of incomplete DJHjoints. Whereas IGK-Kde and TCRD rearrangements were rare, TCRG rearrangements were present in 50% of cases and involved mainly Vγ11 or Vγ9 together with a Jγ1.3./2.3 gene segment, an unusual combination among t(4;11)-negative B-cell precursor ALL. Oligoclonality was found in about 30% as assessed by heterogeneous IGH and TCRG rearrangements. Our data are in line with transformation of a precursor cell at an early stage of B-cell development but retaining the potential to differentiate to the pre-B cell stage in vivo. Although a distinct difference between infant and older childhood cases with t(4;11) became evident, no age-related biological features were found within the childhood age group. In contrast to infants with t(4;11)-positive ALL, childhood cases had a relatively low cumulative incidence of relapse of 25% at 3.5 years with BFM-based high-risk protocols.,
Erasmus MC: University Medical Center Rotterdam

Mann, G., Cazzaniga, G., van der Velden, V., Flohr, T., Csinady, E., Paganin, M., … Panzer-Grümayer, E. R. (2007). Acute lymphoblastic leukemia with t(4;11) in children 1 year and older: The 'big sister' of the infant disease?. Leukemia, 21(4), 642–646. doi:10.1038/sj.leu.2404577