Cancer environmental factors

Carcinogenic agents include chemicals in the environment, such as aniline and benzene, which are associated with the development of bladder cancer and leukemia, respectively. Environmental factors, such as excessive sun exposure, also may result in cancer. Viruses, including the human papilloma virus and hepatitis B, maybe associated with the development of cancer. Some of the chemotherapy agents cause secondary cancers after therapy has been completed. Numerous factors may contribute to the development of cancer. 

Colon cancer occurs at a much higher rate in industrialized parts of the world such as North America and Europe, whereas the lowest rates are seen in less-developed areas, suggesting that environmental and dietary factors influence the development of colon cancer.2 In addition to these environmental factors, colon cancers are known to develop more frequently in certain families, and genetic predisposition to this cancer is well known. 

Besides age, the development of colorectal cancer appears to be caused by variety of dietary or environmental factors, comor-bid disease states, and genetic susceptibility to the disease. Table 88-1 lists well-known risk factors for developing colon cancer. Epidemiologic studies of worldwide incidence of colorectal... 

Ovarian cancer is associated with certain dietary and environmental factors as well. A diet that is high in galactose and animal fat and meat increases the risk of ovarian cancer, whereas a vegetable-rich diet is suggested to decrease risk.4,8 Although controversial, exogenous factors such as asbestos and talcum powder use on the perineal area also have been suggested to increase the risk of ovarian cancer.4,8... 

Armstrong, B., Doll, R., Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices, IntJ Cancer, 15, 617, 1975. 

Radiation is one of the most important known environmental stimuli of cancer development. This environmental factor becomes especially dangerous for humans living in the areas affected by irradiation from nuclear accidents. Earlier we found that the administration of a mixture of vitamin E and a-lipoic acid to children living in the area of Chernobyl nuclear accident significantly and synergistically suppressed leukocyte oxygen radical overproduction [211]. Thus a-lipoic acid and a-lipoic acid + vitamin E supplements may be of interest as antioxidant preventive agents for the treatment of radiation-induced cancer development. 

Brinton LA, Devesa SS (1996) Etiology and pathogenesis of breast cancer. Epidemiologic factors. Incidence, demographics and environmental factors. In Harris JR, Lippman ME, Morrow M, Heilman S (eds) Diseases of the breast Lippincott-Raven, Philadelphia, pp 159-168... 

The primary goal of the Childhood Cancer Research Program is to identify environmental factors responsible for childhood cancer. Specific aims are to understand the interactions between environmental causes of childhood cancer and host factors that influence reaction to environmental exposure. 

It has been proposed that in as many as 70-80% of the cases of human cancer environmental chemicals are the causative factors (JL). There is no reason why similar estimates would not be valid for animals. It is noteworthy that the occurrence of chemical carcinogens is widespread in the aquatic environment. For example, of the PAH s, BP is found in the concentration of 50 to 100 yg/m3 in what is considered moderately polluted surface water in waste water as much as 100,000 yg/m3 has been measured (6l). Several... 

The International Agency for Research on Cancer (lARC) monographs (Figure 3.3) identify environmental factors that can increase the risk of human cancer. These include chemicals, complex... 

Cancer is a disease present in people and animals in which the stracture and normal function of body tissues are disrupted. The exact etiology of most types of cancer is unknown. However, it is well known that infections, environmental factors (chemical substances, foreign particles, radiation), and genetic factors can induce transformation of normal cells to neoplastic cells, i.e. those that multiply and function abnormally. 

Many dietary and environmental factors have been implicated as possible etiologic factors in the development of pancreatic cancer, but no definite causal relationships have been established. The strongest evidence points to cigarette smoking as a risk factor associated with pancreatic cancer (20-24). Occupational exposure to certain chemicals has also been linked to pancreatic carcinoma (25). Others in the high-risk group include stone miners, cement workers, gardeners, textile workers, and leather tanners (17,26). 

California Air Resources Board/Office of Environmental Health Hazard Assessment, Benzol a] pyrene as a Toxic Air Contaminant (1994) Office of Environmental Health Hazard Assessment/California Environmental Protection Agency, Air Toxics Hot Spot Program Risk Assessment Guideline, Part II Technical Support Document for Describing Available Cancer Potency Factors (1998) Collins et al. (1998). 

Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Air Toxics Hot Spot Program Risk Assessment Guideline Part II Technical Support Document for Describing Available Cancer Potency Factors, 1998. 

C. Malaveille, Unit of Endogenous Cancer Risk Factors A. t Mannetje, Environmental Cancer Epidemiology... 

Hormone-related cancers of the breast, ovary, endometrium, and prostate have been reported to vary by as much as 5 to 20-fold between populations. Migrant studies indicate that the difference is largely attributable to environmental factors rather than genetics [219,220]. The highest rates of these cancers are typically observed in populations with Western lifestyles that include relatively high fat, meat-based, low fiber diets, whereas the lowest rates are typically observed in Asian populations with Eastern lifestyles that include plant-based diets with a high content of phytoestrogens [219,221]. 

Michigan contamination episode (Henderson et al. 1995 Hoque et al. 1998), but the results are only suggestive due to factors such as small number of cases, insufficient information on know n breast cancer risk factors, and confounding exposures to other organochlorine chemicals. The evidence for an association betw een breast cancer and PCBs is also not conclusive (Agency for Toxic Substances and Disease Registry 2000), and the hypothesis that environmental exposure to PCBs can cause breast cancer in humans is controversial (Safe and Zacharewski 1997 Wolff and Toniolo 1995). Overall, tlie evidence for an association between breast cancer and PBBs is inconclusive and needs further study. 

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