Prognostic impact of deletions at 1p36 and numerical aberrations in Ewing tumors

Ewing's sarcoma, peripheral primitive neuroectodermal tumors, and Askin tum ors are referred to as Ewing tumors (ETs), and are characterized by high MI C2 expression and a t(11;22)(q24;q12) or other rearrangements involving 22q 12. In addition to these constant aberrations, facultative numerical and st ructural aberrations have been reported: gains of chromosomes 8 and 12, the unbalanced translocation t(1;16), and deletions at the shots arm of chromo some 1. To evaluate the frequency and to study the biological impact of the se facultative aberrations, we analyzed tumor specimens from 58 ET patients by classical cytogenetics and/or in situ hybridization techniques and comp ared these data with clinical parameters. Gains of chromosomes 8 and 12 wer e detected in 55% (32/58) and 24% (14/58) of the cases, respectively. Loss of chromosome 16 or der(16)t(1;16) chromosomes were found in 20% (10/51); d eletions at 1p36 were observed in 18% (9/51) of the cases evaluated. The pr esence of these aberrations did not correlate with age and sex of the patie nts, with the location of the primary tumor or with the extent of disease a t diagnosis by chi-square analysis and Fisher's eras test. Patients with tu mors harboring gains of chromosome 8 showed a slightly better clinical outc ome (n = 14/30, P = 0.17), whereas gains of chromosome 12 did not influence the clinical outcome (n = 7/30, P = 0.63). However, Kaplan and Meier analy sis revealed that deletions at the short arm of chromosome I were associate d with an unfavorable outcome in patients with localized disease (n = 6/22; P = 0.004). Genes Chromosomes Cancer 24:243-254, 1999. (C) 1999 Wiley-Liss , Inc.