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Current Strategies of Cancer Chemoprevention,
 13th International Symposium on Cancer.
July 6-9, 1993, Sapporo, Japan, 1993. (1993):18

Chemoprevention of mammary cancer by monoterpenes (Meeting abstract).
Gould MN
Dept. of Human Oncology  Univ. of Wisconsin-Madison  Madison WI 53792

ABSTRACT
Monoterpenoids are formed by the condensation of two isoprene  molecules. These compounds are commonly and primarily produced by plants and are found in many commonly consumed fruits and vegetables  including citrus fruits and food flavoring such as mints. The simplest monocyclic monoterpene, limonene, has been shown to prevent a variety of organ-specific cancer in rodent models. In addition,  dietary limonene can cause the complete regression of established rat mammary carcinomas without toxicity. Histopathological study of terpene-induced regressing carcinomas suggest that a cytostatic/redifferentiation process is associated with regression.  The cellular effects of these terpenes, thus far demonstrated, can be  divided into those associated with the increasing cellular levels of  specific gene products and those associated with inhibiting enzyme  activities associated with the mevalonate/lipid metabolism pathway  including protein prenyl-transferases. Monoterpene exposure has been  shown to result in both increased cellular levels of enzymes that could block DMBA initiation of mammary cancer and of receptor  proteins that might be associated with prevention during  promotion/progression stages and tumor regression. Interestingly,  limonene was also found to increase the cellular levels of TGF beta in regressing tumors. Monoterpenes have a broad range of chemopreventive activities in a variety of organ-specific models systems. This coupled with lack of toxicity at effective dose levels encourage further evaluation as both agents for the prevention and treatment of cancer.

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