[Multi-stop carcinogenesis model for adult T-cell leukemia].

A multi-step model of the carcinogenesis for adult T-cell leukemia-lymphoma (ATL) has been reviewed here according to the authors observations. Epidemiological studies demonstrated that in most japanese ATL cases the disease developed from those who acquired infection of the causal agent, human T-cell lymphotropic virus type 1 (HTLV-1), during early infancy, probably through breast-feeding. Therefore, the latency period between the acquisition of HTLV-1 and clinical manifestation of ATL can be represented by the age of disease onset. It has been demonstrated by us that the age distribution of ATL onset can be described by a single Weibull distribution function, which is considered to be a feasible mathematical model for multistep carcinogenesis. Based on the present model, it is assumed that age-dependent accumulation of nearly five leukemogenic events, most likely somatic mutations, within the target cell(s) might be required prior to the disease onset.