A modified method of carcinogenesis induction in the DMBA hamster cheek pouch model of squamous neoplasia

BACKGROUND: The classic hamster cheek pouch model of squamous cell neoplasia requires triweekly application of 9,10-dimethyl-1,2-benzanthracene (DMBA) on tissues for 20 weeks. This study describes a new methodology for induction of neoplasia using a sustained-release delivery of carcinogen that is less labor intensive with decreased risk to personnel. METHODS: Cotton sutures were impregnated with DMBA and coated with silicone elastomer. These sutures were then placed in the cheek pouch of animals, were harvested at weekly intervals, and residual DMBA was measured confirming sustained release. Carcinogenesis was compared in Syrian hamsters grouped into classic triweekly painted model (n = 10), sustained-release DMBA (n = 19), sustained-release with weekly painting (n = 17), and control (n = 10). RESULTS: The sustained-release implants resulted in a 90% yield of squamous neoplasia at 20 weeks, similar to the classic painted model but with less handling of the carcinogen and the animals. CONCLUSIONS: This model is safer for personnel, time efficient, and effective for inducing carcinogenesis.