Breast cancer may be linked to the use of deodorants, a new report claims.
The potential link was established after tests on women who had mastectomies found high levels of aluminium in breast tissue.
Aluminium, which has already been linked to cancer by other studies, is used as an antiperspirant in most deodorants to stop the skin sweating. The antiperspirant part is made up of 90 per cent aluminium.
In 17 breast cancer patients studied the research found "significantly higher" levels of aluminium in the underarm region of the breast where antiperspirants are sprayed than in other parts of the breast.
Recent research has linked breast cancer with the use of aluminium-based, underarm antiperspirants.
There is also a higher incidence of tumours in the breast area closest to the underarm, but it has not been established why. The report could not say whether the aluminium came from the antiperspirant - it may come from other sources.
Also the study could not definitely link the two - as the tumours may attract the metal in the tissue to them, rather than be a cause of the tumour.
Dr Chris Exley, from Keele University, carried out the tests on tissue from the 17 women who had mastectomies while patients at Wythenshawe Hospital, Manchester.
Dr Exley said, "You could make a leap of faith that the two could be linked. It is only on 17 individuals but the data we have showing a higher distribution of aluminium in the underarm is statistically significant. It could not have happened by chance."
Dr Sarah Cant, senior policy and information officer at Breakthrough Breast Cancer, said: "There is no reliable scientific evidence to suggest a link between deodorant or antiperspirant use and breast cancer.
"A large number of scientific studies have investigated breast cancer risk factors, however there is no good evidence to suggest that either deodorant or antiperspirant use or exposure to aluminium can increase the risk of developing this disease.
"This very small study in the Journal of Inorganic Biochemistry does not provide any further proof. Breast cancer is a complex disease and its causes are unknown for the majority of the 44,000 women diagnosed each year in the UK.
"That's why Breakthrough Breast Cancer supports the Breakthrough Generations Study - which is the largest study of its kind in the UK to investigate the causes of breast cancer and to gain information on causes that might be preventable."