title: Distinct chromosomal imbalances in pleomorphic and in high-grade dedifferentiated liposarcomas.
abstract: Using comparative genomic hybridization, DNA copy number changes were studied in 14 pleomorphic liposarcomas and compared to those detected in high-grade areas of 9 dedifferentiated liposarcomas. A total of 251 gains and 84 losses were detected. The most frequent gains involved subregions of chromosomal arms 12q and 20q (70% each), 5p (57%), 6q and 9q (52% each), 1q, 7p and 17p (48% each), 1p (43%), 6p and 17q (39% each), 20p and 22q (35% each) as well as 7q and 12p (30% each). The same subregions were also affected by 30 high level amplifications. The most frequent losses were found in subregions of chromosomal arms 13q (35%) as well as 11q and 12p (30% each). Overall, gains of chromosomal material were more frequent than losses (p < 0.001). There were significant differences in the frequency and distribution of recurrent chromosomal imbalances between pleomorphic liposarcomas and the dedifferentiated areas of dedifferentiated liposarcomas. Gains of chromosomal material detected predominantly in pleomorphic liposarcomas involved subbands 5p13-p15 (p < 0.010), 1p21 (p < 0.019), 1q21-q22 (p < 0.040) and 7q22 (p < 0.049). Conversely, high level amplifications within chromosomal subregion 12q13-q21 were only found in the dedifferentiated components of dedifferentiated liposarcomas (p < 0.001). Overall, both gains and the less pronounced losses of chromosomal material were more frequent in pleomorphic than in dedifferentiated liposarcomas (p < 0.001 and p < 0.025, respectively). These results show that pleomorphic liposarcomas display a considerable number of recurrent chromosomal imbalances that are essentially different from those present in high-grade areas of dedifferentiated liposarcomas. Therefore, genetic data are considered as a helpful diagnostic adjunct for the discrimination between these 2 types of liposarcoma. The overall higher frequency of chromosomal imbalances in pleomorphic as compared to dedifferentiated liposarcomas could account for the more aggressive biological behavior of pleomorphic relative to dedifferentiated liposarcoma types.
authors.affiliation: Institute of Pathology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Ralf J
authors.initials: RJ
authors.lastname: Rieker
authors.forename: Stefan
authors.initials: S
authors.lastname: Joos
authors.forename: Christine
authors.initials: C
authors.lastname: Bartsch
authors.forename: Frank
authors.initials: F
authors.lastname: Willeke
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwarzbach
authors.forename: Marta
authors.initials: M
authors.lastname: Otaño-Joos
authors.forename: Sybille
authors.initials: S
authors.lastname: Ohl
authors.forename: Josef
authors.initials: J
authors.lastname: Högel
authors.forename: Thomas
authors.initials: T
authors.lastname: Lehnert
authors.forename: Peter
authors.initials: P
authors.lastname: Lichter
authors.forename: Herwart F
authors.initials: HF
authors.lastname: Otto
authors.forename: Gunhild
authors.initials: G
authors.lastname: Mechtersheimer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation; D002869:Chromosome Aberrations; D002874:Chromosome Mapping; D002877:Chromosomes, Human / Q000235:genetics*; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008080:Liposarcoma / Q000235:genetics* / Q000473:pathology; D019656:Loss of Heterozygosity; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D012983:Soft Tissue Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D004273:DNA, Neoplasm