Myeloid antigen positive acute lymphoblastic leukemia with the Philadelphia translocation and a jumping translocation of 1q in a child

A case of Philadelphia chromosome positive acute lymphoblastic leukemia with partial trisomy of chromosome 1q involving chromosome 13 as the acceptor-A novel cytogenetic finding

The Philadelphia (Ph) chromosome is infrequently found in acute lymphoblastic leukemia and is associated with poor prognosis. We present a case of Ph chromosome positive B cell-acute lymphoblastic leukemia with the partial trisomy of chromosome 1q involving chromosome 13 as the acceptor which has never been reported in the English literature. Jumping translocation (JT) of chromosome 1 is rare and is associated with disease progression and poor prognosis. Herein, we report the first case of Ph chromosome positive B cell-acute lymphoblastic leukemia with coexisting jumping translocation of chromosome 1 leading to trisomy of chromosome 1q. Dismal prognosis associated with synchronous presence of a Ph chromosome and JT leading to a partial trisomy of chromosome 1q may carry significant prognostic and therapeutic implications. This may be an incidental finding and further studies with large patient cohorts and clinical outcomes are needed to definitively determine the predictive value of this cytogenetic finding.

Jumping translocations

Jumping translocations (JT) are uncommon constitutional or acquired chromosome rearrangements involving one donor and several recipient chromosomes. They occur in various pathologic conditions and the mechanism of their formation remains elusive. A review of the literature showed that the major localizations of the breakpoints of JTs in human samples are nonrandomly located in pericentromeric and telomeric regions of chromosomes. Interestingly, comparison of the localization of the chromosomal breakpoints and of presence of interstitial DNA repeats showed differences between constitutional and acquired JTs suggesting differences in the mechanisms for the genesis of JTs and their consequences.

Jumping translocation of 17q11∼qter and 3q25∼q28 duplication in a variant Philadelphia t(9;14;22)(q34;q32;q11) in a childhood chronic myelogenous leukemia

The virtually obligatory presence of the Philadelphia chromosome may suggest a causal homogeneity, but chronic myelogenous leukemia (CML) is a clinically heterogeneous disease. This may be a consequence of the variable BCR breakpoints on chromosome 22 and of nonrandom secondary chromosomal abnormalities. We present the case of a boy, age 12, investigated in blastic phase of CML. Karyotyping with conventional and multiplex fluorescence in situ hybridization (FISH and M-FISH) karyotyping, complemented with reverse transcriptase-polymerase chain reaction, identified a variant Philadelphia translocation t(9;14;22)(q34;q32;q11) involving a cryptic BCR/ABL fusion with formation of the p190(Bcr-Abl) oncoprotein. M-FISH revealed also an unbalanced jumping translocation of 17q11 approximately qter alternatively present on chromosomes 14 or 20, apparently hithertofore unreported in hematological malignancies. Another secondary aberration, dup(3)(q25q28), was revealed by multipoint interphase FISH (mpI-FISH). Gain of this region is known in adult hematological malignancies and solid tumors, suggesting its general involvement in tumor initiation or progression (or both), regardless of tissue origin.