Species susceptibilities to chemical carcinogens: a critical appraisal of the roles of sex hormones (endocrine status) and nutritional influences.

The objective of the present evaluation was to assess the possible roles of the sex hormones (endocrine status), nutritional influences and other factors in regard to species susceptibilities to chemical carcinogens. By reviewing the experimental and epidemiological data, it was concluded that there are compelling indications, particularly in the fields of physiology and metabolism, to conclude the limited usefulness of the various animal species in sex hormone research. The findings allow only restricted inferences for the human species. On the other hand, as far as nutritional influences on cancer development are concerned, similar mechanisms operate with regard to high or low calorie, fat, protein and carbohydrate intakes in animals and humans. Consequently, the findings obtained in laboratory animals can be transmitted with some modifications to the human species. This assessment is the continuation of an earlier work, which appraised the roles of genetic and viral agents, concerning species susceptibilities to chemical carcinogens.