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

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.