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Using animal models and in vitro experiments, new research examines a potential link between aluminum-based deodorants and breast cancer. Puneet Vikram Singh/Getty Images
  • Headlines have alleged a link between aluminum salts in antiperspirants and breast cancer.
  • Human epidemiological studies have found no association between the use of antiperspirants or deodorants and breast cancer.
  • Two laboratory studies have shown that when animal cells absorb aluminum, they show chromosome changes.
  • The findings do not prove that aluminum salts cause cancer, and doctors have called for further research.

Rates of breast cancer have been increasing in the United States and many other Western societies in recent decades, and much research focuses on trying to determine why. Recent headlines have implicated aluminum salts, found in antiperspirants, as a potential cause of breast cancer.

Now, two laboratory studies have shown aluminum absorption by animal cells and subsequent genetic changes in those cells. The researchers suggest this indicates that environmental aluminum may be responsible for increasing rates of breast cancer.

The studies, from an international team of scientists and published in the International Journal of Molecular Sciences, looked first at whether aluminum chloride was absorbed by animal cells in vitro, then examined the effect on those cells.

In the first study, published late last year, mammary epithelial cells from immunodeficient mice were cultured with aluminum chloride (AlCl3). The researchers found that AlCl3 rapidly increased chromosomal structural abnormalities in these cells.

The team then injected these cells into immunocompetent mice. Of the 20 mice injected with the cells cultured in AlCl3, 17 developed tumors at the injection site, whereas none of the 10 mice injected with control cells did.

The second study, published last month, investigated the absorption of aluminum by hamster cells cultured with AlCl3. The researchers found that the V79 cells used did incorporate aluminum. At a concentration of 10 micromoles, there was no significant effect on cell viability, but there was a significant increase in chromosome double-strand breaks.

The authors express concern that these surviving cells could then replicate and propagate the karyotypic abnormalities. Karyotypic abnormalities are a feature of many cancers.

They suggest “special consideration should be given to the long-term consequences of regular low-dose absorption [of aluminum] for human carcinogenesis.”

Dr. Janie Grumley, MD, surgical breast oncologist, director of the Margie Petersen Breast Center at Providence Saint John’s Center, and an associate professor of surgery at Saint John’s Cancer Institute in Santa Monica, CA, commented on the findings for Medical News Today: “These researchers are doing lab work on animals to gain an understanding of the interactions between aluminum and human tumor genesis. I applaud their efforts and am glad they are doing this research. I definitely want to hear more about it.”

However, she added, “Animal studies are good for figuring out how something works but do not necessarily apply to human situations.”

The authors state that their results are “compelling evidence that aluminum is a human carcinogen.” Dr. Kotryna Temcinaite, senior research communications manager at Breast Cancer Now, disagrees. “That cells [being] exposed to aluminum salts in laboratory experiments led to genomic instability is not evidence that aluminum salts are carcinogenic,” she said.

However, she added, “These papers provide evidence of the need for further evaluation to see if aluminum compounds can be classified as carcinogens.”

Dr. Grumley also questioned whether these studies provide evidence of a link: “As a physician and clinician, I take it with a grain of salt. You cannot extrapolate – we don’t inject [deodorants] into the system, and we are not mice. ”

“I would never use these studies to tell women they can’t use deodorants.”

– Dr. Janie Grumley

Dr. Temcinaite added, “Our bodies also have several defense mechanisms that detect and get rid of cells that aren’t quite right, so genomic instability alone may not always be enough to result in cancer.”

Epidemiological studies investigating aluminum and breast cancer have found no evidence of a link or been inconclusive. A 2021 study found no significant association between aluminum-containing antiperspirants and breast cancer. In 2008, an analysis of 19 studies concluded that there was no scientific evidence to support the hypothesis of a possible link between antiperspirants and breast cancer.

Dr. Temcinaite said: “More research is needed before we can draw any firm conclusions about humans. In these experiments, non-human cells were exposed to aluminum salts in artificial conditions and were then analyzed for DNA damage or transplanted into mouse mammary glands. This approach doesn’t represent well enough what would happen when people use products containing aluminum salts, such as cosmetics that would be used on the skin.”

She added, “There are currently no strong epidemiological studies that link breast cancer risk and antiperspirant use, and ultimately [the] carcinogenicity of aluminum has not yet been proven.”

Dr. Grumley advised that people can reduce their breast cancer risk in other ways, recommending people “[f]ocus on the other risk factors that have a bigger impact, such as diet and exercise.”