Trace metals and over-expression of metallothioneins in bladder tumoral lesions: a case-control study.
BACKGROUND
Previous studies have provided some evidence of a possible association between cancer and metallothioneins. Whether this relates to an exposure to carcinogenic metals remains unclear.


METHODS
In order to examine the association between the expression of metallothioneins and bladder tumors, and to compare the levels of arsenic, cadmium, chromium, lead and nickel in animals with bladder tumors and animals without bladder tumors, 37 cases of bovine bladder tumors and 17 controls were collected. The detection and quantification of metallothioneins in bladder tissue of both cases and controls was performed by immunohistochemistry. And the quantification of metals in tissue and hair was assessed by inductively coupled plasma - mass spectrometry.


RESULTS
Increased expression of metallothioneins was associated with bladder tumors when compared with non-tumoral bladder tissue (OR = 9.3, 95% CI: 1.0 - 480). The concentrations of cadmium, chromium, lead and nickel in hair of cases were significantly higher than those of controls. However, as for the concentration of metals in bladder tissue, the differences were not significant.


CONCLUSIONS
Though the sample size was small, the present study shows an association between bladder tumors and metallothioneins. Moreover, it shows that concentrations of metals such as cadmium, chromium, lead and nickel in hair may be used as a biomarker of exposure.
Amaral
André F S
AF
Spanish National Cancer Research Centre (CNIO), Genetic and Molecular Epidemiology Group, Madrid, Spain. aamaral@cnio.es
Cymbron
Teresa
T
Gärtner
Fátima
F
Lima
Manuela
M
Rodrigues
Armindo S
AS
D000236:Adenoma / Q000737:chemistry / Q000378:metabolism / Q000662:veterinary; D000818:Animals; D002277:Carcinoma / Q000737:chemistry / Q000378:metabolism / Q000662:veterinary; D002417:Cattle; D002418:Cattle Diseases / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D006197:Hair / Q000737:chemistry; D006391:Hemangioma / Q000737:chemistry / Q000378:metabolism / Q000662:veterinary; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D010212:Papilloma / Q000737:chemistry / Q000378:metabolism / Q000662:veterinary; D012307:Risk Factors; D014131:Trace Elements / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000662:veterinary*
D008670:Metals; D014131:Trace Elements; D008668:Metallothionein