Original article
Loss of 17p is a major consequence of whole-arm chromosome translocations in hematologic malignancies

https://doi.org/10.1016/j.cancergencyto.2006.10.013Get rights and content

Abstract

To ascertain the distribution of whole-arm translocations (WATs) and their consequential imbalances in hematologic malignancies, we analyzed the imbalances related to chromosomes involved in clonal, acquired WATs in 140 consecutive tumors with WATs and near-diploid karyotypes. Tumors for analysis were obtained from a survey of the cytogenetic database in the Department of Medical Genetics, Henry Ford Health System, Detroit, MI. Of the 140 tumors, 9 had balanced WATs; the remaining 131 had WATs that rarely or never involved chromosome X, Y, 2, 3, 4, 6, 19, or 20. Chromosome arms were lost more often than they were gained, and short arms were lost more often than long arms, except for chromosomes 7 and 16 (more long arms lost than short) and chromosome 11 (both arms equally lost). The long arm of chromosome 1 was the only arm gained with substantial frequency, in 26% of tumors. Of WATs that resulted in gain of 1q, short arm of chromosome 7 and acrocentric long arms were involved in 47 and 24%, respectively. Acrocentric chromosomes were involved in acquired WATs in 45% of tumors (the D-group acrocentrics more than the G-group), and were more likely to be involved in non-Robertsonian than Robertsonian translocations (P < 0.001, normal test). Loss of 17p was the most common short-arm loss (23% of tumors) and often occurred as part of complex karyotypes suggestive of disease progression. The present findings show that acquired whole-arm chromosome translocations in hematologic malignancies are nonrandom, commonly involve acrocentric chromosomes, and often result in loss of 17p, which is often associated with advanced disease and poor prognosis in a wide spectrum of hematologic malignancies.

Introduction

Whole-arm translocations (WATs) reportedly are rare in hematologic malignancies [1]. Nonetheless, a study of acquired Robertsonian translocation in acute leukemia and lymphoma [2], as well as a review of the current cancer cytogenetic database [3], show that WATs are recurrent findings that may be observed as sole anomalies in hematologic malignancies. Indeed, about 11 different unbalanced WATs—der(1;7)(q10;q10), der(1;14)(q10;q10), der(1;15)(q10;q10), der(1;18)(q10;q10), der(7;12)(q10;q10), der(13;14)(q10;q10), der(14;21)(q10;q10), der(17;18)(q10;q10), der(1;7)(q10;p10), der(1;7)(p10;q10), and der(9;18)(p10;q10)—have been reported as recurrent sole anomalies in hematologic malignancies [3], suggesting that these may be primary changes.

Barring the remote possibility of the existence of tumorigenesis-relevant centromeric genes that may be disrupted during WATs, the most likely major consequence of WAT is the genomic imbalance resulting from the gain and loss of whole chromosome arms and the genes that reside on them—in particular given that the majority of WATs reported in the literature have been unbalanced [3].

Apart from the study documenting acquired Robertsonian translocations in acute leukemia and lymphoma [2], and studies on specific WATs, we know of no studies addressing the distribution and profile of imbalances generated by whole-arm translocations in hematologic malignancies.

The present study was undertaken to ascertain the distribution of whole-arm chromosome translocations and their consequential chromosomal imbalances among cytogenetically characterized hematologic malignancies.

Section snippets

Materials and methods

The cytogenetics laboratory database in the department of Medical Genetics, Henry Ford Health system was searched to retrieve all samples that had been cytogenetically characterized between January 1995 and June 2006 because of a hematologic malignancy and that had acquired WAT.

The cytogenetic information retrieved was obtained from cytogenetic analyses performed on metaphase cells prepared from short-term culture of bone marrow aspirate, lymph node, or leukemia peripheral blood samples.

Results

The search covered 14,603 hematologic malignancy samples that had been successfully analyzed cytogenetically. After eliminating duplicate or multiple samples from the same patient, 11,717 samples remained for our analysis. Of these, 164 (1.4%) had clonal acquired whole-arm chromosome translocations. Isochromosomes were not included as WATs.

Of the 164 samples with WATs, 24 had near-triploid or near-tetraploid unbalanced translocations. Because polyploidy may complicate a proper assessment of the

Discussion

WATs have often been considered uncommon in hematologic malignancies. Recent published data [2], [3], however, as well as the present findings, show that they do occur as recurrent sole anomalies. Indeed, besides the well-recognized der(1;7)(q10;p10) commonly associated with acute myeloid leukemia, myelodysplastic syndromes, and myeloproliferative disorders [8], some WATs have now been documented as primary changes associated with specific disease entities [9], [10].

The profile of imbalances

References (19)

There are more references available in the full text version of this article.

Cited by (0)

View full text