Retained heterodisomy for chromosome 12 in atypical lipomatous tumors: implications for ring chromosome formation.

Fredrik Mertens, Ioannis Panagopoulos, Tord Jonson, David Gisselsson Nord, Margareth Isaksson, Henryk Domanski, Nils Mandahl

Research output: Contribution to journalArticlepeer-review


Atypical lipomatous tumor (ALT) is an intermediate malignant mesenchymal tumor that is characterized by supernumerary ring chromosomes and/or giant rod-shaped marker chromosomes (RGMC). Fluorescence in situ hybridization ( FISH) and molecular genetic analyses have disclosed that the RGMCs always contain amplified sequences from the long arm of chromosome 12. Typically, RGMCs are the sole clonal changes and so far no deletions or other morphologic aberrations of the two normal-appearing chromosomes 12 that invariably are present have been detected. The mechanisms behind the formation of the RGMCs are unknown, but it could be hypothesized that RGMC formation is preceded by trisomy 12 or, alternatively, that ring formation of one chromosome 12 is followed by duplication of the remaining homolog. The latter scenario would always result in isodisomy for the two normal-appearing chromosomes 12, whereas the former would yield isodisomy in one-third of the cases. In order to investigate these possible mechanisms behind ring formation, we studied polymorphic loci on chromosome 12 in 14 cases of ALT showing one or more supernumerary ring chromosomes and few or no other clonal aberrations at cytogenetic analysis. The molecular genetic analyses showed that the tumor cells always retained both parental copies of chromosome 12, thus refuting the trisomy 12 and duplication hypotheses. Copyright (C) 2004 S. Karger AG, Basel.
Original languageEnglish
Pages (from-to)33-38
JournalCytogenetic and Genome Research
Issue number1
Publication statusPublished - 2004

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Pathology, (Lund) (013030000), Division of Clinical Genetics (013022003)

Subject classification (UKÄ)

  • Medical Genetics


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