t(1;19) without detectable E2A rearrangements in two t(14;18)-positive lymphoma/leukemia cases.

Translocation t(1;19)(q23;p13) plays a crucial role in the pathogenesis of childhood pre-B cell leukemia and results in the formation of a fusion gene E2A-PBX1 that encodes a hybrid transcription factor with oncogenic potential. Here we describe two cases, one follicular lymphoma and one acute lymphoblastic leukemia/lymphoma, characterized by a complex karyotype including t(14;18), t(8;14), as well as t(1;19). Molecular studies in both cases failed to show rearrangements of the E2A gene. These results suggest that the t(1;19) found as a secondary chromosome change in t(14;18)-positive lymphoma/leukemia might be a molecular variant of the t(1;19) that is typical of childhood pre-B cell leukemia.