Distinct patterns of chromosome abnormalities characterize childhood non‐Hodgkin's lymphoma

Summary. We report here cytogenetic studies of a series of 23 childhood non-Hodgkin's lymphomas (NHL), a group that has previously not been subjected to detailed cytogenetic analysis. Combining our results with data from 25 tumours in the published literature, we have performed the first cytogenetic analysis of a large series of childhood NHL. Our results show that the cytogenetic changes encountered in NHL of children are distinct and may be different from those seen in NHL of adults reflecting the previously recognized differences in histological presentation and clinical behaviour of the two entities. Thus, the most frequently occurring translocation in B-cell lesions in children was t(8;14)(q24;1q32). Other translocations frequently seen in adults such as t(14;18)(q32;q21),t(11;14)(q13;q32) and t(3;22)(q27;q11) were either rare or so far not seen in children, although reciprocal translocations appeared to be generally prevalent in childhood NHL. Combining our data with those in the published literature, we have identified two new recurring translocations [t(1;17)(p36;q21) and t(1;14)(p36;q22)], and a recurring duplication [dup(11)(q13;q23)] in this group of lymphomas. In addition, our literature survey identified a third recurring translocation [t(5;14)(q23;q32)] which was previously reported in two cases of childhood NHL. Our analysis also showed differences in the types of nonrandom translocations between childhood NHL and acute lymphoblastic leukaemia (ALL) in children suggesting that biologically these entities are different from one another. This study thus uncovers patterns of chromosome change associated with childhood lymphoma thus providing new opportunities for investigation of their clinical significance by correlation analysis and biological significance by molecular analysis.