Clustering of deletions on chromosome 13 in benign and low-malignant lipomatous tumors.
Deletions and structural rearrangements of the long arm of chromosome 13 are frequently observed in benign and low-malignant lipomatous tumors, but nothing is known about their molecular genetic consequences. We assessed the karyotypes of 40 new and 22 previously published cases (35 ordinary lipomas, 15 spindle cell/pleomorphic lipomas, 2 myxolipomas, 1 angiomyxolipoma and 9 atypical lipomatous tumors) with chromosome 13-abnormalities, and found bands 13q12-22 to be frequently affected. Twenty-seven cases with structural abnormalities within this region were selected for breakpoint and deletion mapping by metaphase fluorescence in situ hybridization (FISH), using a set of 20 probes. Deletions were found in 23 of 27 cases. The remaining 4 cases had seemingly balanced rearrangements. The breakpoints were scattered but clustered to band 13q14, and in all cases with unbalanced abnormalities, a limited region within band 13q14 was partially or completely deleted. A deletion within band 13q14 was found together with a breakpoint on the other homologue in 5 cases, 4 of which could be tested further with regard to the status of the retinoblastoma (RB1)-gene. In all 4 cases, only 1 copy of the gene was deleted. In addition to the breaks and deletions in the vicinity of the RB1-locus, several other regions of 13q were recurrently affected, e.g., in the vicinity of the hereditary breast cancer (BRCA2; 13q12)- and lipoma HMGIC fusion partner (LHFP; 13q13)- genes. Our findings strongly indicate that deletion of a limited region (approximately 2.5 Mbp) within 13q14, distal to the RB1-locus, is of importance in the development of a subset of lipomatous tumors.
Dahlén
Anna
A
Department of Clinical Genetics, University Hospital, Lund, Sweden. anna.dahlen@klingen.lu.se
Debiec-Rychter
Maria
M
Pedeutour
Florence
F
Domanski
Henryk A
HA
Höglund
Mattias
M
Bauer
Henrik C F
HC
Rydholm
Anders
A
Sciot
Raf
R
Mandahl
Nils
N
Mertens
Fredrik
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018206:Angiolipoma / Q000235:genetics* / Q000473:pathology; D002872:Chromosome Deletion; D018244:Chromosomes, Artificial, Yeast / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D015342:DNA Probes; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008067:Lipoma / Q000145:classification / Q000235:genetics* / Q000473:pathology; D008080:Liposarcoma / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014178:Translocation, Genetic
D015342:DNA Probes