Living near toxic Superfund sites linked to aggressive breast cancer

Breast cancer is the second leading cause of cancer death among women, according to the American Cancer Society. Now, three recent studies by researchers at the Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, have discovered links between breast cancer, Superfund sites and social adversity.

Even more alarming, a National Institutes of Health study indicates that some particularly aggressive and treatment-resistant forms of breast cancer, such as triple-negative breast cancer, are on the rise. In the United States, more than 300,000 people are diagnosed with breast cancer each year, accounting for approximately 15.5% of all annual cancer diagnoses.

The increase in cases of breast cancer – particularly aggressive and difficult-to-treat types – highlights the need to examine potential environmental factors contributing to these worrying trends. Along the same lines, in Florida, the presence of 52 active Superfund sites has become a priority, prompting members of the Sylvester Community Advisory Committee to raise awareness and connect with the cancer center on these issues.

“Members of our community raised concerns that where they lived was making people sick,” said Erin Kobetz, Ph.D., MPH, epidemiologist and associate director for community outreach and engagement at Sylvester and the Judy H. Schulte Senior Endowed Chair in Cancer Research. “The overwhelming majority of people who talked about it lived in a neighborhood relatively close to a Superfund site. There is growing evidence that living in neighborhoods close to these sites is associated with poor health outcomes.”

Although health and Superfund sites have been studied for decades, the links between environmental degradation, pollution and breast cancer remain understudied, Dr. Kobetz said. So she put together a multidisciplinary team of doctors, basic scientists and epidemiologists to dive and study breast cancer and the proximity of Superfund sites in Florida. Using Sylvester’s SCAN360 data portal, his team was able to retrieve granular data on South Florida neighborhood characteristics and cancer risks.

Breast Cancer and Superfund Sites

The first study looked at more than 21,000 cases of breast cancer diagnosed in Florida between 2015 and 2019. Kobetz and his co-authors wondered whether proximity to a Superfund site was linked to whether the breast cancer was metastatic. Researchers found that living in the same census tract as at least one Superfund site increased the risk of metastatic breast cancer by about 30 percent.

The researchers then turned to the specific study of triple negative breast cancer (TNBC) and found that living near a Superfund site is also associated with an increased risk of this aggressive subtype of breast cancer. Kobetz and his colleagues wanted to further explore the links between TNBC and a certain pollutant, particulate matter 2.5 (PM2.5), which is a pollutant smaller than 2.5 microns. They report that higher exposure to PM2.5 leads to a higher risk of TNBC in South Florida.

These two studies were published in Scientific reports And Cancer epidemiology, biomarkers and prevention. Together, they highlight the risk that simply living near a Superfund site can pose in terms of breast cancer.

“These studies, along with federal funding priorities, increasingly emphasize the role of the environment in health outcomes,” Kobetz said. “We need to better understand how environmental conditions may drive variability in cancer outcomes.”

Biomarkers in tumors

Clinicians and researchers are concerned about environmental factors in a patient’s health journey, but there is still much to learn about how these factors can influence diseases at the molecular level.

That’s why Aristeidis Telonis, Ph.D., research assistant professor of biochemistry and molecular biology at the Miller School, wanted to study what might leave a chemical fingerprint in patients, a biomarker or even shape cancer progression.

The team, co-led by Kobetz, analyzed breast cancer samples from 80 patients in the Miami area. They went further than just genetic testing of DNA; they also checked instruction notes (epigenome) and real-time messages (RNA) that show how DNA is put into action.

The researchers then compared the genetic biomarkers to a composite measure of neighborhood context and elements known to influence health outcomes. They observed that patients in neighborhoods with fewer health promotion resources were more likely to have these biomarkers and suffer from more aggressive forms of breast cancer.

“This index of deprivation is very strongly associated with more aggressive breast cancers,” Telonis said. “It’s a simple but very important correlation.” The study is published in Cancer epidemiological biomarkers and prevention and is among the first to delve deeper into these associations with molecular events inside a tumor, he said. The findings open the door to highly personalized care, with treatment plans that can better address the specific tumor conditions presented by a patient.

“The goal is that when a patient comes in, the doctor not only assesses the characteristics of the tumor, but also considers the patient’s resources and what that may mean at the molecular level,” Telonis said. “Ultimately, this should help inform treatment.”

Community first for a healthy future

Kobetz emphasized that this work directly addresses community concerns.

“We have a signal, and our community advisory committee compels and encourages us to pursue it,” Kobetz said. “The community had a point of view, and we now have empirical and scientific data to suggest that their concerns may be valid. These studies are the first pieces of the puzzle that will help us determine what we should focus on next.”