Metal Interactions in Carcinogenesis: Enhancement, Inhibition

A silent epidemic of environmental metal poisoning?

“…In general, the assessment of carcinogenicity to a suspected metal or its compounds has been limited to high levels of exposure in the workplace environment or as a result of accidental spills or food contamination (Nordberg and Andersen, 1981). Current evidence that metal pollution induces cancer in the general population, is scanty and inconclusive (Nordberg and Andersen, 1981).…”

“…In general, the assessment of carcinogenicity to a suspected metal or its compounds has been limited to high levels of exposure in the workplace environment or as a result of accidental spills or food contamination (Nordberg and Andersen, 1981). Current evidence that metal pollution induces cancer in the general population, is scanty and inconclusive (Nordberg and Andersen, 1981). However, the debate has not properly addressed two key issues (a) the possible effects of widespread low level exposures to a mixture of carcinogenic contaminants (Fern, 1971;Blumer and Reich, 1980;Nisbet and Karch, 1983), and (b) immuno-suppression caused by toxic metals and its role in cancer induction and metastasis.…”

Characterization of gene expression changes associated with MNNG, arsenic, or metal mixture treatment in human keratinocytes: application of cDNA microarray technology.

“…Cells (1 × 10 4 /cm 2 ) were plated in 25-cm 2 culture flasks in triplicate. Viable cells at 5,8,10,12,15, and 17 days after initial plating were counted by trypan blue exclusion on a hemocytometer. Culture medium was changed every 3 days.…”

“…Additionally, the activity of a metal in any given tissue is dependent on its speciation and metabolism (6). To further complicate the picture, metals have been shown to interact at multiple levels and, most likely, modify one another's cytotoxicity and/or carcinogenic potential (8)(9)(10)(11). As a result, we are still a long way from a fundamental understanding of the actions of metals or metal mixtures at the cellular level, particularly as they relate to toxic end points.…”

Antimony in lung, liver and kidney tissue from deceased smelter workers.

“…According to Wester (35) and also Nordberg & Andersen (26), it is at present impossible to show any single cause for the development of lung cancer in smelter workers. In addition to smoking, a documented risk factor, both toxic gases and potential carcinogenic substances with a long biological half-time in the lung, eg, antimony, must be considered.…”