The debate was thought to be over and aluminium salts totally uncorrelated with the development of breast cancer. A study conducted by researchers at the University of Geneva has relaunched it today, highlighting the harmful effects of aluminium salts in antiperspirants on human breast cells in vitro. If this study does not constitute formal proof of the responsibility of aluminium salts in the development of breast cancer, it certainly raises the strongest suspicions.
This cell biology study, conducted by researchers from the University of Geneva (UNIGE) and funded mainly by the Meyer Foundation, the Geneva League against Cancer and the Foundation for the Fight against Cancer and for Medical-Biological Research, was published in the scientific journal Journal of Applied Toxicology.
In its press release, the University of Geneva states that its results challenge the safety of these salts on breast cells.
The press release
The increase in the number of breast cancers in industrialized countries in recent decades is accompanied by a change in the anatomical distribution of this cancer, which now develops mainly in the outer part of the mammary gland, near the armpits. This location raises the question of the responsibility of deodorants containing aluminium salts (aluminium hydrochloride and aluminium chloride), which have been shown to penetrate the skin, in the formation of breast cancer.
To date, little or no experimental or epidemiological data have been available to support or refute this hypothesis.
A UNIGE team, coordinated by Stefano Mandriota, a biology researcher at the Faculty of Medicine, and André-Pascal Sappino, an honorary professor and breast cancer specialist, conducted a series of in vitro experiments that revealed the harmful effects of aluminium salts on human breast cells.
Confirmed adverse effects
Models of normal human mammary epithelial cells have been cultured in an environment containing doses of aluminum salts 1,500 to 100,000 times lower than those found in conventional deodorants. After several weeks, the researchers found that aluminum salts have harmful effects on mammary cells and lead to abnormal behaviour, which corresponds to the first phases of malignant transformation of the cells.
Through a phenomenon that scientists call “contact inhibition”, normal cells, when cultured, stop proliferating when they come into contact with each other.
Dr. Mandriota’s team discovered that breast cells that have been exposed to aluminum salts lose this contact inhibition and continue to multiply: they behave like cells on the path of malignant transformation.
This study also highlighted the increasing number of double-stranded DNA breaks in mammary cells exposed to aluminum salts, caused by an alteration in the cell proliferation process. These breaks could be related to the induction of the malignant transformation of these mammary cells, caused by aluminum salts.
In addition, the researchers analyzed the behaviour of mammary cells exposed to aluminum salts in soft agar assay gels. Where normal cells remain isolated, cells exposed to aluminum salts form colonies.
This behaviour is typical of tumour cells and cells on the path of malignant transformation.
“Although this study does not confirm that aluminium salts, present in conventional deodorants, cause the development of breast cancer, it is scientific evidence of the harmfulness of these salts on breast cells,” concludes Stefano Mandriota.
For further information
• See this information on the UNIGE website (in French only)