Registration Dossier

Administrative data

Description of key information

No adequate experimental animal studies are available to evaluate the carcinogenicity of zinc compounds in humans.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Study duration:
chronic
Species:
mouse

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

On the basis of the existing information it can be concluded that there is no conclusive evidence for carcinogenic activity of any of the zinc compounds considered in this chemical safety report.

Additional information

There are a range of epidemiological studies that investigated the association between zinc exposure either through occupational activities or food supplementation and increased cancer risks. While no associations were found between occupational zinc exposure and excess cancer risk, the main association that has been made in this context is related to dietary/supplemental zinc and prostate cancer risk.

In contrast to established clinical and experimental evidence that prostate cancer is associated with a decrease in the zinc uptake, numerous epidemiology studies and reports of the effect of dietary and supplemental zinc on the incidence of prostated cancer have provided divergent, inconsistent and inconclusive results which range from adverse effects of zinc, protective effects of zinc and no effect of zinc on the risk of prostate cancer. Clinical and experimental studies have established that zinc levels are decreased in prostate cancer and support a role of zinc as a tumor suppressor agent. Malignant prostate cells in situ are incapable of accumulating high zinc levels from circulation (Franklin et al.,2005; Costello and Franklin, 2006; Franklin and Costello, 2007).

In a recent critical assessment of epidemiology studies regarding dietary/supplemental zinc and prostate cancer risk, Costello et al.,concluded that epidemiological studies have not provided an established relationship for any effect or lack thereof of dietary/supplemental zinc on the risk of prostate cancer. Proclamations of an association of dietary/supplemental zinc and increased prostate cancer are based on inconclusive and uncorroborated reports (Costello et al.,2007).


Justification for selection of carcinogenicity via oral route endpoint:
only 1 experimental animal study available but several epidemiological studies regarding dietary/supplental zinc and prostated cancer are available, however, not providing an established association of dietary/supplemental zinc and increased prostate cancer

Justification for selection of carcinogenicity via inhalation route endpoint:
no experimental animal study available but several epidemiological studies indicating no association between occupational zinc exposure and excess cancer risk