Carcinogenesis

Cancer occurs when the body s own (somatic) cells undergo uncontrolled replication and growth. As with mutations, cancer often results from alterations in cellular DNA. Many cancers occur as apparently random events. Study of the human genome has shown genetic characteristics indicative of a propensity to certain kinds of cancers. For experimental purposes, animals have been bred that have inherited tendencies toward certain kinds of cancers. Some biological agents including hepad-naviruses or retroviruses are known to cause cancer. 

Safrole (from sassafras) a natural product that requires bioactivation 

Benzo(a)pyrene, a synthetic chemical that requires bioactivation 

Bi (chloromethyl)ether, a synthetic compound that does not require bioactivation 

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Difluoronaphthalene [315-52-6] is prepared from 4-fluoro-l-naphthylarnine by the Balz-Schiemann reaction. 1,4-Difluoronaphthalene is used in chemical carcinogenesis studies as a synthon for highly condensed difluoro—polycycHc aromatic hydrocarbons (273). 

A toxic component of braken fern, perhaps either quercetin (105) or ptaquiloside, a glucoside (106), has a mixed history of carcinogenicity. It is sometimes impHcated in an increased incidence of bladder cancer in animals and esophageal cancer in humans. Multiple other dietary components seem to either promote or interfere with its action, and the significance of braken fern in human carcinogenesis remains unproven. 

NTP Technical Teport on the Toxicology and Carcinogenesis Studies of Ethylene Glycol (CAS No. 107-21-1) in B6C3F1 Mice (Feed Studies), NIH Pubhcation... 

P. D. Lawley and co-workers, eds., Topics in Chemical Carcinogenesis University of Tokyo Press, Tokyo, Japan, 1972, 272 pp. 

Not only is TCDO a potent therapeutic agent in acute radiation syndrome, but treatment using TCDO from days 4—11 after TBI increases the survival rate in rats for up to one year, protects against the development of late GI ulcers, and also reduces the development of y-ray-induced leukemias and malignant epitheHal tumors, but not sarcomas (202). The anticarcinogenic effect of TCDO maybe related to the inhibition of PGs, which promote carcinogenesis, or to immunostimulation, which may result in a more effective elimination of malignant cells. 

Animal studies have shown that teas are effective in blocking or slowing carcinogenesis (121,131,133). Administration of teas or tea polyphenols to mice or rats have also been shown to decrease oxidative biomarkers, suggesting that tea polyphenols act as antioxidants (125,134). 

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