The effects of end point overdispersions on the validity of single-dose tumorigenicity assays

Overdispersion can be found in tumor incidence and tumor latency end point values obtained by the conventional assays that are being used to assess the tumorigenicity of neoplastic cells growing in tissue culture. Failure to account for such wide variations in end point data can lead to incorrect assessments of the neoplastic cell tumorigenic phenotype and misinterpretations of data relating genetic functions to tumor-forming capacity. This problem suggests the need for more detailed analyses of the relationships that exist between tumor cell dose and the parameters being used to measure tumorigenicity.