Stress, diet and cancer : a study on incidence and growth of malignant tumors in rats

In the present study, it was our aim to study some potentially carcinogenic factors like stress, and dietary lipids within the following framework: -the carcinogenic factors studied have to be administered in such a way that the animals are kept in a condition of "wellbeing" as much as possible. Particularly, acute injurious effects have to be prevented. -the factors have to be present chronically (lifelong), or at least subchronically {period of at least one month). -the tumor , model has to be comparable with a human tumor, in ·histo-pathological appearance, as well as in biological behavior. -the "control" of the suspected carcinogenic factor shall be in such a way that the above mentioned considerations with regard to noxiousness, etc, are identical for the control non-carcinogenic factor. -the biological variability of the tumor models as well as the methodological variability of the parameters have to be small. Furthermore, it is our assumption that when a certain environmental factor causes an altered tumor risk, this factor will trigger some biochemical processes, which will result in measurable changes in the homeostasis of the individual. It will be clear that a choice had to be made, which of the many biochemical processes should be monitored. With our choice we do not suggest that, the biochemical processes not studied, do not play a role in the relationship between environmental factors and increased cancer risk.