title: [Loss of heterozygosity induced by cyclophosphamide at tk locus in human lymphoblastoid cell line TK6].
abstract: OBJECTIVE
  Human lymphoblastoid cell line TK6 was used to investigate TK gene mutation frequency and the loss of heterozygosity (LOH) induced by cyclophosphamide (CP).
  
  
  METHODS
  Relative survival, mutation frequency at tk locus induced by CP (+S9) after 4 h treatment were detected. DNA isolated from mutants in the control culture and CP treatment group was analyzed for LOH.
  
  
  RESULTS
  Exposure to CP for 4 h decreased relative survival, induced TK gene mutation in a dose-dependent manner. Doubling time of normally and slowly growing mutants was (14.6 +/- 1.74) h and (35.8 +/- 3.78) h respectively. The percentage of hemizygous LOH in CP-induced mutants (50%) was 2.4 times than that of the control (20.7%).
  
  
  CONCLUSIONS
  Great damage to TK gene is the main cause of mutation induced by CPin TK6 cells.
authors.affiliation: National Chengdu Center for Safety Evaluation of Traditional Chinese Medicine, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhan
authors.forename: Li-shi
authors.initials: LS
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Suzuki
authors.initials: S
authors.lastname: Takayoshi
authors.forename: Honma
authors.initials: H
authors.lastname: Masamitsu
authors.forename: De-sheng
authors.initials: DS
authors.lastname: Wu
mesh_terms: D002460:Cell Line; D003520:Cyclophosphamide / Q000633:toxicity*; D006801:Humans; D019656:Loss of Heterozygosity; D008214:Lymphocytes / Q000166:cytology*; D009154:Mutation; D013937:Thymidine Kinase
chemical_list: D003520:Cyclophosphamide; D013937:Thymidine Kinase