Parabens may increase breast cancer cell growth in Black women

  • Researchers investigated the effects of parabens—a class of preservatives used in cosmetic and pharmaceutical products—on Black breast cancer cell lines.
  • They found that parabens may increase growth in Black breast cancer cell lines.
  • The researchers conclude that their findings can be used by all women who are at a high risk of developing breast cancer.

In the United States, Black women are 39% more likely to die from breast cancer than white women. Black women are also more likely to develop breast cancer under the age of 40 than other ethnic groups.

Exposure to compounds known as parabens, which are used as preservatives in hair and personal care products, has been linked to a higher risk of breast cancer. Most of these studies, however, have involved breast cancer cell lines of European ancestry.

Until now, few, if any, studies have investigated the effects of parabens on breast cancer cell lines with West African ancestry.

Knowing how parabens affect the growth of breast cancer in Black women could help develop public health recommendations that reduce breast cancer risk among Black women.

In a recent study, researchers investigated how parabens affect the growth of Black breast cancer cell lines. They found that while parabens increased the growth of a Black breast cancer cell line, they did not increase growth in a white breast cancer cell line.

“The effects we observe on cell growth and hormone-related gene expression in this study give us a clue that paraben exposure may promote breast cancer progression,” Dr. Lindsey S. Treviño, assistant professor at the Department of Population Sciences at City of Hope, a cancer research and treatment organization in Los Angeles, and one of the study’s authors, told Medical News Today.

“[The findings are] important because we know that hair products marketed to and used by Black women contain parabens. Parabens have been found at higher concentrations in urine samples from Black women in the United States compared to other racial or ethnic groups.”
— Dr. Lindsey S. Treviño

The study was presented at the Endocrine Society’s annual meeting in Atlanta, Georgia.

West African vs. European cell lines

For the study, the researchers treated two breast cancer cell lines—one from West African ancestry and the other from European ancestry—with methylparaben (MP), propylparaben (PP) or butylparaben (BP).

They also treated the cell lines with an estrogen receptor antagonist to see whether any observed effects were mediated by estrogen.

In the end, the researchers found that BP increased the number of cancer cells from West African ancestry but not European ancestry.

They also found that BP and PP, but not MP, increased the expression of estrogen-regulated genes in both cell lines, suggesting that their effects may be mediated by estrogen.

The researchers say that these preliminary experiments suggest that parabens promote growth in both cell lines, with a potentially greater effect on those of West African ancestry.

Underlying mechanisms 

When asked what might explain the differing effects of parabens on Black and white breast cancer cell lines, Dr. Xiaoting Zhang, director of the Breast Cancer Research Program at the University of Cincinnati College of Medicine, who was not involved in the study, told MNT:

“This is a very interesting finding, and it appears that at least part of these differential effects of parabens could be due to genetic or epigenetic differences in the estrogen receptor pathway of these two cell lines,” he said.

“These could include allelic gene variations in the estrogen receptor itself and/or changes in the expression level or activities of other components of the estrogen receptor pathway such as transcriptional coactivators, kinases, small RNAs, etc,” he explained.

The researchers concluded that their findings suggest that parabens also cause harmful effects on breast cancer cells in Black women.

When asked about the limitations of the study, Dr. Zhang said, “Since this study only used one cell line each of European and West African ancestry, it will be important to examine more cell lines of each origin to see how common this phenomenon is and to dissect the underlying molecular mechanisms.”

“It will be highly critical to further study its effect not only in cultured breast cancer cells but also in animal models and eventually in humans,” he elaborated.

“Although the findings in the study are intriguing and it could suggest there is a potentially higher overall breast cancer risk in West African women due to exposure to parabens, we must be cautious in drawing the conclusion as this is still at an early stage and needs further studies.”
— Dr. Xiaoting Zhang

When asked how these findings could help reduce breast cancer risk, Dr. Treviño said:

“These data contribute to the goal of the Bench to Community Initiative (BCI). BCI is co-led by me at City of Hope and Dr. Dede Teteh at Chapman University and brings together scientists and community members to understand the sociocultural perspective of hair and identity for Black women, the types of hair products they use, and how these products could increase their risk for breast cancer.”

“Ultimately, we will use the information we find to develop community interventions to help Black women reduce their exposure to parabens and other endocrine-disrupting chemicals found in their personal care products,” she concluded.

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