Atypical rearrangement involving 3′-IGH@ and a breakpoint at least 400 Kb upstream of an intact MYC in a CLL patient with an apparently balanced t8;14q24.1;q32 and negative MYC expressionReport as inadecuate




Atypical rearrangement involving 3′-IGH@ and a breakpoint at least 400 Kb upstream of an intact MYC in a CLL patient with an apparently balanced t8;14q24.1;q32 and negative MYC expression - Download this document for free, or read online. Document in PDF available to download.

Molecular Cytogenetics

, 6:5

First Online: 01 February 2013Received: 05 October 2012Accepted: 13 December 2012

Abstract

The t8;14q24.1;q32, the cytogenetic hallmark of Burkitt’s lymphoma, is also found, but rarely, in cases of chronic lymphocytic leukemia CLL. Such translocation typically results in a MYC-IGH@ fusion subsequently deregulating and overexpressing MYC on der 14q32. In CLL, atypical rearrangements resulting in its gain or loss, within or outside of IGH@ or MYC locus, have been reported, but their clinical significance remains uncertain. Herein, we report a 67 year-old male with complex cytogenetic findings of apparently balanced t8;14 and unreported complex rearrangements of IGH@ and MYC loci. His clinical, morphological and immunophenotypic features were consistent with the diagnosis of CLL.

Interphase FISH studies revealed deletions of 11q22.3 and 13q14.3, and an extra copy of IGH@, indicative of rearrangement. Karyotype analysis showed an apparently balanced t8;14q24.1;q32. Sequential GPG-metaphase FISH studies revealed abnormal signal patterns: rearrangement of IGH break apart probe with the 5’-IGH@ on derivative 8q24.1 and the 3’-IGH@ retained on der 14q; absence of MYC break apart-specific signal on der 8q; and, the presence of unsplit 5’-MYC-3’ break apart probe signals on der 14q. The breakpoint on 8q24.1 was found to be at least 400 Kb upstream of 5’ of MYC. In addition, FISH studies revealed two abnormal clones; one with 13q14.3 deletion, and the other, with concurrent 11q deletion and atypical rearrangements. Chromosome microarray analysis CMA detected a 7.1 Mb deletion on 11q22.3-q23.3 including ATM, a finding consistent with FISH results. While no significant copy number gain or loss observed on chromosomes 8, 12 and 13, a 455 Kb microdeletion of uncertain clinical significance was detected on 14q32.33. Immunohistochemistry showed co-expression of CD19, CD5, and CD23, positive ZAP-70 expression and absence of MYC expression. Overall findings reveal an apparently balanced t8;14 and atypical complex rearrangements involving 3’-IGH@ and a breakpoint at least 400 Kb upstream of MYC, resulting in the relocation of the intact 5’-MYC-3’ from der 8q, and apposition to 3’-IGH@ at der 14q. This case report provides unique and additional cytogenetic data that may be of clinical significance in such a rare finding in CLL. It also highlights the utility of conventional and sequential metaphase FISH in understanding complex chromosome anomalies and their association with other clinical findings in patients with CLL. To the best of our knowledge, this is the first CLL reported case with such an atypical rearrangement in a patient with a negative MYC expression.

KeywordsMYC-IGH FISH CLL Microarray Electronic supplementary materialThe online version of this article doi:10.1186-1755-8166-6-5 contains supplementary material, which is available to authorized users.

Ina Amarillo, Peter H Bui contributed equally to this work.

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Author: Ina Amarillo - Peter H Bui - Sibel Kantarci - Nagesh Rao - Brit S Shackley - Rolando García - Carlos A Tirado

Source: https://link.springer.com/



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