DELETION OF 14Q IN COHORT OF 560 PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKAEMIA

Background:

Deletion of 14q is rare but recurrent aberration in B-cell malignancies, especially in chronic lymphocytic leukaemia (CLL). A limited number of studies focused on characterization of patients with del(14q). Reindl et al. (2010) suggested that del(14q) is associated with short time to treatment. We analysed CLL patients from Czech republic by conventional cytogenetic analysis, fluorencence in situ hybridization (FISH) and molecular methods and characterized the cases with del(14) in detail.

Aims:

The purpose of the current study was to focus on del(14q) in cohort of 560 CLL patients, to evaluate the incidence and to analyse additional cytogenetic abnormalities, IGVH mutation status and clinical outcomes.

Methods:

In a period between 2008 to 2012, 560 cases with CLL were investigated. Conventional cytogenetics was performed on peripheral blood or bone marrow samples cultured in medium with CpG-oligonucleotides and IL-2 for 72 hours. I-FISH was performed on unstimulated cells for detection of IGH@ rearrangement, + 12, del(11q), del(13q) and del(17p). The range of del(14q) was determined by multicolor banding. For analysis of the IGVH mutation status, monoclonal immunoglobulin rearrangements were amplified by PCR from cDNA. PCR products were purified in agarose gel and analysed by direct sequencing.

Results:

A total of 519/560 (92,7 %) cases were succesfully stimulated for metaphase analysis. Del(14q) was detected in 12 cases (12/519, 2,3 %) and it was mostly intersticial (11/12). It showed variable size but clustered at specific chromosomal bands. FISH revealed loss of 3´IGH@ flanking sequences (8/12). In 5 cases del(14q) was found as sole abnormality, whereas additional aberrations were identified in 7 cases. Two cases had complex karyotype. IGHV status was unmutated in 9/11 cases.

Summary / Conclusion:

Cytogenetic results are highly relevant in defining the prognosis of CLL patients. I-FISH is standard method for detection of important chromosomal aberrations. However, metaphase cytogenetic analysis reveals another abnormalities which may change the prognosis of patients defined by FISH. Our results are consistent with those of other studies. We confirmed the low occurence of del(14q), association with unmutated IGVH and the presence of additional aberrations together with del(14q).

Email address: lucie.dostalova@lab-agel.cz

Keywords: Chronic lymphocytic leukemia, Cytogenetic abnormalities, IGH

Abstrakta v časopise Haematologica 2013, Suppl1

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