Chronic Disease and Environmental Epidemiology, Minnesota Department of Health, 85 East 7th Place, P.O. Box 64882, St. Paul, MN 55164-0882, USA.

A 70% excess of mesothelioma, an asbestos-related cancer, has been reported among men in northeastern Minnesota, where iron mining has been the major industry. The Minnesota Department of Health has studied iron miners who developed mesothelioma to identify possible sources of asbestos exposure. A database of all Minnesota residents diagnosed with mesothelioma between 1988 and 1996 was linked to a database of approximately 72,000 current and former Minnesota iron-mining employees to identify cases who had ever worked in the mining industry. The job histories of the cases were examined to determine if any of their jobs could have involved exposure to commercial asbestos. Seventeen individuals diagnosed with mesothelioma in Minnesota between 1988 and 1996 were found to have worked in the iron mining industry. Of the 15 for whom adequate work histories were available, 14 had identifiable sources of exposure to commercial asbestos in jobs held both inside and outside of the mining industry. The time between employment in these asbestos-exposed occupations and the diagnosis of mesothelioma is consistent with the 20 or more year latency period that has been observed in other studies of this cancer.

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School of Public Health, University of Sydney, NSW 2006, Australia.

Exposure-response relationships between the relative risk of lung cancer and quantitative measures of exposure to asbestos are available from a number of epidemiological studies. Meta-analyses of these relationships have been published by Lash et al. (1997) [Lash, T.L., Crouch, E.A.C., Green, L.C., 1997. A meta-analysis of the relation between cumulative exposure to asbestos and relative risk of lung cancer. Occup. Environ. Med. 54, 254-263] and Hodgson and Darnton (2000) [Hodgson, J.T., Darnton, A., 2000. The quantitative risks of mesothelioma and lung cancer in relation to asbestos exposure. Ann. Occup. Hyg. 44, 565-601]. In this paper, the risks derived in these meta-analyses have been compared. Lash et al., concentrated on process and found that the risk of lung cancer increased as the asbestos is refined by processing. Hodgson and Darnton concentrated on fibre type and found that the risk was highest for exposure to amphibole asbestos (crocidolite and amosite), lowest for chrysotile and intermediate for mixed exposure. Some of the differences between the conclusions from the two meta-analyses are a consequence of the choice of studies included. The range of asbestos types included in the studies in the analysis of Hodgson and Darnton was wider than that in Lash et al., enabling differences between fibre types to be analyzed more readily. There are situations where occupational exposure to chrysotile asbestos has shown no detectable increase in risk of lung cancer. Taconite miners have shown no increased risk of mortality due to lung cancer.

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Department of Pathology, Haartman Institute and HUSLAB, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland. hanna.vauhkonen@helsinki.fi

Cancer results from multiple genomic changes that affect DNA and its gene expression. The DNA sequences may be gained, lost or amplified, or translocated into different parts of the genome to form a fusion gene with oncogenic properties. The occurrence of specific chromosomal aberrations may be restricted to only one cancer type and it may be considered a primary carcinogenic event. Furthermore, the aberration profiles may be used to cluster tumors with similar origins. A variety of techniques exist for the detection of specific chromosomal and gene expression changes. However, the etiology of these molecular alterations remains unclear. Here we discuss the roles of Helicobacter pylori and asbestos burden as carcinogens that cause gastric cancer, mesothelioma and lung cancer. Copyright (c) 2007 S. Karger AG, Basel.

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University Department of Medicine, National Centre for Asbestos Related Diseases, University of Western Australia, Perth, Australia.

Chemotherapy and immunotherapy can be either synergistic or antagonistic modalities in the treatment of cancer. Cytotoxic chemotherapy not only affects the tumor but also targets dividing lymphocytes, the very cells that are required to develop an immune response. For this reason, chemo- and immunotherapy have been seen as antagonistic. However, cell death can be immunogenic and the way in which chemotherapeutic drug kills a tumor cell is likely to be an important determinant of how that dying cell interacts with the immune system and whether the interaction will lead to an immune response. When a cell dies as the result of infection, the immune system responds rapidly and the system of Toll-like receptors (TLR) plays a key role in this process. In this review, we will briefly summarize the intracellular signaling pathways that link TLR ligation with immune activation and we will address the questions where and how TLRs recognize their targets.

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National Institute of Environmental and Occupational Health, Post Office Box 3, Raanana 43100, Israel.

Grunerite asbestos (amosite) has been shown in epidemiological and experimental animal studies to cause lung cancer, mesothelioma and pulmonary fibrosis commonly referred to as asbestosis. An overview of the human and experimental animal studies describing the health hazards of grunerite asbestos (amosite) is presented. Of the many human studies describing the health hazards of asbestos, only three factories using mainly, if not exclusively, grunerite asbestos (amosite) have been studied. The first is a series of reports on a cohort of 820 workers from a plant located in Paterson, NJ. Among this cohort, 18.7% died of lung cancer and 17 mesotheliomas occurred. The Paterson factory closed in 1954 and moved to Tyler, Texas where it operated until 1972. Among the 1130 former workers in the Tyler plant 6 mesotheliomas were reported with 15.8% lung cancer mortality. The third grunerite asbestos (amosite) exposed cohort was an insulation board manufacturing facility in Uxbridge, United Kingdom. Here 17.1% of the workers died of lung cancer and 5 mesotheliomas occurred. The lung content from 48 Uxbridge workers was analyzed by analytical transmission electron microscopy for mineral fibers. The relationship between grunerite asbestos (amosite) concentrations in the lung correlated with grades of fibrosis and asbestos bodies and was lower than the concentration found in the cases with malignant tumors. The lung cancer cases contained more grunerite asbestos (amosite) than mesothelioma cases, and in the cases of non-malignant disease the concentrations were still lower. In both types of malignancies the concentration of grunerite asbestos (amosite) was very high-over a billion fibers per gram of dried lung tissue. Occupational exposure to airborne concentrations of between 14 and 100 fibers of grunerite asbestos (amosite) per milliliter after 20 year latency causes marked increases in lung cancer, mesothelioma and pulmonary fibrosis (asbestosis).

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