The problem of latency in the development of tumors following exposure to nickel compounds.

Six previously published animal studies of tumor production have been reviewed, in order to relate time interval between exposure to nickel and development of tumor formation. Biopsies at intervals before final tumor formation, in some of these experiments, were reviewed to define interim changes between exposure and tumor diagnosis. Correlation between rat and human life span was used to suggest a latency of human tumor expectancy following exposure to nickel.