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 p oint values obtained by the conventional assays that are being used to assess the tumorigenicity of neoplastic cells growing in tissue cultu re. Failure to account for such wide variations in end point data can lead to incorrect assessments of the neoplastic cell tumorigenic pheno type and misinterpretations of data relating genetic functions to tumo r-forming capacity. This problem suggests the need for more derailed a nalyses of the relationships that exist between tumor cell dose and th e parameters being used to measure tumorigenicity.