Carcinogen tumor promoter, relationship

Phenol has been tested in animals for carcinogenicity by the oral and dermal routes, but results are equivocal. In a chronic NCI cancer bioassay (NCI 1980), a significant incidence of tumors (pheochro-mocytomas of the adrenal gland, leukemia, or lymphomas) occurred only in male rats exposed to the lowest dose level (2,500 ppm, 277 mg/kg/day) of phenol but not in male or female mice or male rats exposed to a higher dose level (5,000 ppm, 624 mg/kg/day). Since tumors occurred only in males in one of the two species tested, and since a positive dose-response relationship was not established, this study does not provide sufficient evidence to conclude that phenol is carcinogenic when administered by the oral route. Dermal application of phenol has been shown to result in tumors in mice phenol is a tumor promoter when it is applied after the application of the tumor initiator DMBA (Boutwell and Bosch 1959 Salaman and Glendenning 1957 Wynder and Hoffmann 1961). However, this effect occurs at dose levels of phenol that produce severe skin... 

Although there is sufficient data to indicate causal relationships between diet and cancer, drastic changes in dietary guidelines are premature at this time. Since many vitamins and trace elements are anti-carcinogens or anti-promoters, more research should be done on understanding their mechanisms of action. Further research on the role of dietary fiber intake on the inhibition of tumor development is warranted since the mechanism is unknown and there may be adverse effects on nutritional status in high fiber diets. As more information becomes available, it may be possible to modify dietary patterns slightly to reflect decreased consumption of deleterious compounds and increased consumption of beneficial components such that an overall decrease in the risk of diet and cancer could result. 

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