Cancer Induction in Hamsters by Human Type 12 Adenovirus. Effect of Age and of Virus Dose.∗

Summary The susceptibility of newborn hamsters to induction of sarcomas at the site of injection of human type 12 adenovirus decreases rapidly with increasing age at time of injection. For a given age at the time of injection, the incidence of tumors induced is directly proportional to the dose of virus injected. The 50% tumor-inducing dose in hamsters injected when less than one day of age lies between 0.5 and 50 MTCID100 of adenovirus under the conditions of these experiments. Increasing the dose of virus to 1000 MTCID100 produced one tumor among 8 hamsters injected as late as 14 days of age, but none in 3-week or older hamsters.