title: Loss of heterozygosity and the origin of meningioma.
abstract: In some human tumors, loss of particular genes manifested indirectly by loss of heterozygosity for specific RFLPs seems to uncover either heterozygous deletions leading to a gene doses effect or homozygous deletions due to a silent allele at the corresponding locus, both causing the loss of regulatory functions (antioncogenes, suppressor genes). Meningioma, a benign human tumor derived from the coverings of brain and spinal cord, is associated with complete loss, rarely deletion, of one chromosome 22. About 60% of meningiomas exhibit monosomy 22 in all or part of cells; however, about 40% display a normal karyotype. Comparison of constitutional and tumor genomes from 12 patients showed loss of heterozygosity on 22 in three cases, suggesting the involvement of events at the DNA level.
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D002872:Chromosome Deletion; D002892:Chromosomes, Human, Pair 22; D005260:Female; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000235:genetics*; D008579:Meningioma / Q000473:pathology*; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D005819:Genetic Markers