| Popis: |
Cancers of the breast and prostate, which together with those of the ovaries, endometrium and testes are hormone-dependent, are among the most common forms of cancers affecting women and men respectively throughout the developed world (IARC VII 1997, Miller and Sharp 1998). The incidence of breast, prostate, and testicular cancers has risen dramatically in most European and North American countries and in Japan and Australasia since cancer registries were first compiled in the 1960s (WHO/IARC Web site). For instance, women and men born in Generation X in the U.S. and Europe today have twice the risk of developing breast and prostate cancer than their grandparents faced (Dinse et al. 1999). Several lines of evidence indicate that environmental factors, broadly conceived, may account for some of the recent changes in patterns of hormonally dependent cancers. Although rates are about 4 times lower in Asian countries than in European ones, they are increasing most rapidly in the former (Hoel et al. 1992). People who migrate tend to develop the cancer rate of their new countries. Studies of highly exposed workers consistently find that those working with certain plastics, organic solvents, pesticides, and other toxic chemicals tend to have higher risks of several hormonally dependent cancers (Davis and Muir 1995). Dietary factors can be involved in these patterns in two ways. Food constituents, such as dairy and animal protein products, can affect hormonal metabolism directly. In addition, foods can contain contaminants such as growth stimulating substances, pesticides, and packaging materials that can function as endocrine disrupting chemicals (EDCs). In the past decade, a number of major national and international reports have noted the possible role of EDCs for hormone-related illnesses including breast and prostate cancer, including the Weybridge report of the European Environment Agency of 1996 (EUR 17549 1997) and the Royal Society Report on Endocrine Disrupting Chemicals (Royal Soc. 2000). This chapter presents some recent information on the sources of EDCs in the environment, outlines mechanisms by which these materials can increase the risk of hormonally dependent cancers, and discusses insights from geochemistry that may be pertinent to this work. |
