title: Cytogenetic and cellular events during radiation-induced thymic lymphomagenesis in the p53 heterozygous (+/-) B10 mouse.
abstract: OBJECTIVE
  Cellular and cytogenetic events in radiation-induced thymic lymphomagenesis were investigated in the p53 heterozygous (+/-) mouse following a single dose of whole-body irradiation.
  
  
  METHODS
  The loss of the wild-type p53 allele and microsatellite markers of chromosome 11 in thymic lymphomas that developed in the p53 heterozygous (+/-) mouse after irradiation, and the stage at which prelymphoma cells appeared were analysed.
  
  
  RESULTS
  The p53 heterozygous mouse developed thymic lymphomas in a dose-dependent manner. The loss of the wild-type p53 allele (loss of heterozygosity; LOH) occurred in almost all thymic lymphomas induced in the irradiated p53 heterozygous mouse. Cytogenetic analysis for the mechanism of LOH strongly suggested that the loss of the wild-type p53 gene in the lymphomas was caused by duplication of the disrupted allele through either homologous recombination or non-disjunctional chromosome duplication. The assay for prelymphoma cells suggested that a critical event in the development of prelymphoma cells occurred at least 3 weeks after irradiation.
  
  
  CONCLUSIONS
  The loss of the wild-type p53 gene in thymocytes of the p53 heterozygous mouse may precede the development of prelymphoma cells after irradiation and be a valuable marker of radiation-induced leukemogenesis.
authors.affiliation: Radiation Hazards Research Group, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage, Chiba 263-8555, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Mori
authors.forename: H
authors.initials: H
authors.lastname: Kamisaku
authors.forename: H
authors.initials: H
authors.lastname: Tsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Aizawa
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics; D016026:Bone Marrow Transplantation; D003582:Cytogenetics; D016158:Genes, p53; D006579:Heterozygote; D019656:Loss of Heterozygosity; D016399:Lymphoma, T-Cell / Q000209:etiology* / Q000235:genetics* / Q000517:prevention & control; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018895:Microsatellite Repeats; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000235:genetics* / Q000517:prevention & control; D011230:Precancerous Conditions / Q000209:etiology / Q000235:genetics / Q000517:prevention & control; D013601:T-Lymphocytes / Q000276:immunology; D013953:Thymus Neoplasms / Q000209:etiology* / Q000235:genetics* / Q000517:prevention & control
chemical_list: D014408:Biomarkers, Tumor; D008562:Membrane Glycoproteins; C028388:thymus-leukemia antigens