title: Development of a model of tissue with potentially malignant disorders (PMD) in the hamster cheek pouch to explore the long-term potential therapeutic and/or toxic effects of different therapeutic modalities.
abstract: OBJECTIVE
  Given that locoregional recurrences developing from a tissue with potentially malignant disorders (PMD) in oral mucosa are a frequent cause of therapeutic failure, and that tissue with PMD is dose-limiting, the aim of the present study was to develop a model of tissue with PMD to evaluate the long-term therapeutic/toxic effects of different therapeutic modalities.
  
  
  METHODS
  We evaluated 5 carcinogenesis protocols based on topical application of the carcinogen dimethyl-1,2-benzanthracene in the hamster cheek pouch, twice a week for 4, 6, 7, and 8 weeks and the classical 3 times a week for 12 weeks.
  
  
  RESULTS
  Long-term follow-up (8 months after protocol completion) was only possible with the 4- and 6-week carcinogenesis protocols. Tumour development increased progressively with time and aggressiveness of the carcinogenesis protocols. The time at which tumours developed in > or =90% of the animals was at protocol completion (T0) for the 12-week protocol, 1 month post-T0 for the 8-week protocol, 3 months post-T0 for the 7-week protocol and 4 months post-T0 for the 6-week protocol. <40% of the animals in the 4-week protocol developed tumours within the 8 months follow-up period. DNA synthesis rose as a function of time and protocol aggressiveness.
  
  
  CONCLUSIONS
  The 6-week carcinogenesis protocol was selected for long-term studies of different therapeutic modalities in tissue with PMD because it permitted long-term follow-up and guaranteed tumour development in > or =90% of the animals.
authors: Department of Radiobiology, National Atomic Energy Commission, Av. General Paz 1499, B1650KNA San Martin, Provincia de Buenos Aires, Argentina.
authors: Elisa M
authors: EM
authors: Heber
authors: Andrea
authors: A
authors: Monti Hughes
authors: Emiliano C C
authors: EC
authors: Pozzi
authors: Maria E
authors: ME
authors: Itoiz
authors: Romina F
authors: RF
authors: Aromando
authors: Ana J
authors: AJ
authors: Molinari
authors: Marcela A
authors: MA
authors: Garabalino
authors: David W
authors: DW
authors: Nigg
authors: Verónica A
authors: VA
authors: Trivillin
authors: Amanda E
authors: AE
authors: Schwint
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002273:Carcinogens; D002610:Cheek / Q000473:pathology*; D006224:Cricetinae; D004195:Disease Models, Animal; D009061:Mouth Mucosa / Q000473:pathology*; D009062:Mouth Neoplasms / Q000139:chemically induced / Q000473:pathology*
chemical_list: D002273:Carcinogens; D015127:9,10-Dimethyl-1,2-benzanthracene