title: DNA ploidy of primary and recurrent irradiated laryngeal tumors.
abstract: OBJECTIVE
  Radiosensitivity of diploid laryngeal cancers, as compared with that of aneuploid ones, appears to be increased. However, no conclusive data exist. If a causal relationship exists, then recurrent laryngeal cancer after irradiation should predominantly be characterized by aneuploidy.
  
  
  METHODS
  To test this hypothesis we compared ploidy of 24 primarily irradiated laryngeal cancers and their subsequent recurrences. T and N stages were assessed in accordance with the TNM classification system of the UICC. With flow cytometry DNA ploidy was assessed.
  
  
  RESULTS
  1. Ploidy of 16 locally recurrent tumors did not differ from those of primary tumors, i.e. ten and six recurrences of diploid and aneuploid primary tumors, respectively, remained unchanged, 2. recurrences of four aneuploid primary tumors showed diploidy, 3. recurrences of four diploid primary tumors showed aneuploidy.
  
  
  CONCLUSIONS
  The results of our study do not support the hypothesis that recurrent laryngeal cancer after irradiation of the primary tumor is characterized by aneuploidy.
authors.affiliation: Department of Radiotherapy, University Medical Center, Utrecht, The Netherlands. H.STRUIKMANS@RADCL.RUU.NL
authors.forename: Henk
authors.initials: H
authors.lastname: Struikmans
authors.forename: Gert J
authors.initials: GJ
authors.lastname: Hordijk
authors.forename: Henk B
authors.initials: HB
authors.lastname: Kal
mesh_terms: D000782:Aneuploidy; D016009:Chi-Square Distribution; D004273:DNA, Neoplasm / Q000032:analysis*; D004171:Diploidy; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011836:Radiation Tolerance
chemical_list: D004273:DNA, Neoplasm