title: [RB1 and CDKN2A functional defects resulting in retinoblastoma].
abstract: Multiplex methylation-sensitive PCR was employed in studying the methylation of the RB1 and CDKN2A/p16 promoter regions in 52 retinoblastomas. Aberrant methylation inactivating RB1 was detected in 14 (27%) tumors. Methylation of p16 was for the first time observed in retinoblastoma (9 tumors, 17%). Both promoters proved to be methylated in two tumors. In four tumors, aberrant methylation was combined with structural defects of both RB1 alleles. Aberrant methylation of the p16 promoter was the second mutation event in two tumors and was not accompanied by RB1 defects in one tumor. Complex testing for RB1 mutations, loss of heterozygosity, and functional inactivation of the two genes revealed a molecular defect in at least one allele in 51 (98%) tumors.
authors.affiliation: Medical Genetic Research Center, Russian Academy of Medical Sciences, Moscow, 115478 Russia.
authors.forename: O V
authors.initials: OV
authors.lastname: Babenko
authors.forename: V V
authors.initials: VV
authors.lastname: Zemliakova
authors.forename: S V
authors.initials: SV
authors.lastname: Saakian
authors.forename: A F
authors.initials: AF
authors.lastname: Brovkina
authors.forename: V V
authors.initials: VV
authors.lastname: Strel'nikov
authors.forename: D V
authors.initials: DV
authors.lastname: Zaletaev
authors.forename: M V
authors.initials: MV
authors.lastname: Nemtsova
mesh_terms: D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D019175:DNA Methylation; D006801:Humans; D019656:Loss of Heterozygosity; D009154:Mutation; D011401:Promoter Regions, Genetic; D019572:Retinal Neoplasms / Q000235:genetics*; D012175:Retinoblastoma / Q000235:genetics*; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D016160:Retinoblastoma Protein