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A case of mature B‐cell ALL with coexistence of t(1;19) and t(14;18) and expression of the E2A/PBX1 fusion gene
Author(s) -
Rowe David,
Devaraj Prema E.,
Irving Julie A. E.,
Hogarth Linda,
Hall Andrew G.,
Turner Gillian E.
Publication year - 1996
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1996.d01-1754.x
Subject(s) - chromosomal translocation , karyotype , biology , fusion gene , gene expression , microbiology and biotechnology , b cell , gene , immunophenotyping , metaphase , phenotype , t cell , fusion transcript , genetics , chromosome , flow cytometry , antibody , immune system
The translocation t(1;19)(q23;p13) is found in 3–5% of all acute lymphoblastic leukaemias (ALL) and results in the expression of an E2A/PBX1 hybrid gene transcript. This translocation is very closely associated with a pre‐B phenotype. t(14;18) is associated with follicular B‐cell lymphoma and is characterized by over‐expression of the bcl‐2 oncogene. We describe a case of ALL in an adult with a mature B‐cell immunophenotype and a single abnormal cell line with a complex karyotype showing both t(1;19) and t(14;18). Two reports of this phenomenon have been published previously and molecular analysis, where performed, showed the E2A gene was not rearranged, suggesting the t(1;19) was a molecular variant of the established translocation. In contrast, molecular analysis of our case demonstrated expression of the E2A/PBX1 fusion transcript typically associated with t(1;19) in pre‐B ALL but showed it to be present at an extremely low level, despite the abnormal karyotype being found in the majority of metaphase cells. Analysis of bcl‐2 expression showed a significant up‐regulation. A down‐regulation of the E2A/PBX1 hybrid gene as a consequence of the enhanced expression of bcl‐ 2 may be a possible mechanism for this finding.