title: Clonal origin of tumor cells in a plexiform neurofibroma with LOH in NF1 intron 38 and in dermal neurofibromas without LOH of the NF1 gene.
abstract: LOH at the NF1 locus was investigated in 38 neurofibromas of 26 NF1 patients. Only in one of these tumors LOH was observed. In this plexiform neurofibroma of a NF1 patient with a constitutional one base-pair insertion in NF1 exon 4b, a non-random X-inactivation pattern was found, strongly suggesting a clonal origin of the tumor cells. The analysis of X-inactivation patterns allowed the classification of some of the other neurofibromas with regard to the detectability of clonal LOH. In 3 of 6 neurofibromas without LOH amenable to this analysis, a comparable X-inactivation pattern was found in constitutional and neurofibroma derived DNA. A clonal LOH would not have been detected in these tumors. However, we observed a nonrandom pattern in 3 of the 6 neurofibromas, suggesting a clonal origin of the tumor cells. LOH was not detected in these tumors, but could, however, have occurred by mutational events below the level of large somatic deletions, loss of a whole chromosome 17 or somatic recombination.
authors.affiliation: Abteilung Humangenetik, University of Ulm, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Däschner
authors.forename: G
authors.initials: G
authors.lastname: Assum
authors.forename: I
authors.initials: I
authors.lastname: Eisenbarth
authors.forename: W
authors.initials: W
authors.lastname: Krone
authors.forename: S
authors.initials: S
authors.lastname: Hoffmeyer
authors.forename: S
authors.initials: S
authors.lastname: Wortmann
authors.forename: B
authors.initials: B
authors.lastname: Heymer
authors.forename: H
authors.initials: H
authors.lastname: Kehrer-Sawatzki
mesh_terms: D000293:Adolescent; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D004303:Dosage Compensation, Genetic; D005260:Female; D016514:Genes, Neurofibromatosis 1; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D007438:Introns; D009154:Mutation; D009455:Neurofibroma / Q000235:genetics* / Q000473:pathology*; D018318:Neurofibroma, Plexiform / Q000235:genetics* / Q000473:pathology*; D009456:Neurofibromatosis 1 / Q000235:genetics / Q000473:pathology; D011110:Polymorphism, Genetic; D011944:Receptors, Androgen / Q000235:genetics; D011995:Recombination, Genetic; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology*
chemical_list: D005819:Genetic Markers; D011944:Receptors, Androgen