In a groundbreaking discovery, researchers at the University of Colorado Anschutz Medical Campus have revealed that respiratory viruses have the potential to awaken dormant cancer cells in the lungs, posing a significant risk for cancer patients.
This important study builds on the ongoing understanding of how various factors, particularly infections like COVID-19 and the flu, may influence cancer’s progression.
The research led by senior author James DeGregori involved exposing mice to both COVID-19 and influenza to see how these viruses reactivate dormant cancer cells.
“Dormant cancer cells are like the embers left in an abandoned campfire, and respiratory viruses are like a strong wind that reignites the flames,” DeGregori explained.
In their findings, both infections triggered an alarming awakening of dormant cancer cells within the lung model, setting the stage for potential new tumor formation.
The mice study was further substantiated by analyzing human population studies, which indicated a potential risk for individuals with a history of cancer.
In the experimental phase involving mice, the researchers made use of molecular analyses indicating that interleukin-6 (IL-6), a protein released by immune cells in response to both infections and injuries, plays a crucial role in the awakening process of dormant cancer cells.
Their investigation extended to two vast databases of human cases.
In one of the studies, a cohort of over 500,000 participants was examined, including individuals diagnosed with cancer prior to the coronavirus pandemic.
In an investigation led by researchers from the Netherlands and the UK, the focus was on whether contracting COVID-19 elevated cancer-related mortality risk for participants who had survived cancer at least five years before the pandemic began, placing them in a likely remission category.
Among the 487 cancer patients who tested positive for COVID-19, researchers found they faced nearly twice the risk of dying from cancer compared to matched controls who tested negative.
Most striking was that this increased risk was especially pronounced within the first year following infection.
Additionally, another U.S. study using the Flatiron Health database analyzed the incidence of cancer spreading to the lungs comparing those who were COVID-19 positive to those who were negative.
The study tracked 36,216 COVID-19 negative patients against 532 COVID-19 positive patients.
The results indicated that those infected with COVID-19 had a nearly 50 percent higher likelihood of experiencing metastasis to the lungs in comparison to breast cancer patients who did not contract the virus over a four-year follow-up period.
These findings portray a frightening prospect for cancer survivors, highlighting an increased risk of cancer relapse associated with common respiratory viral infections.
It’s important to note that this study was conducted prior to the availability of COVID-19 vaccines, which could potentially alter these risk factors.
The peer-reviewed findings were published in the prestigious journal Nature.
DeGregori emphasizes the long-term impact of respiratory viral infections on cancer survivorship, stating, “These infections can have long-term consequences, but I think what it shows is that they can have consequences that go well beyond the week or two or so that you’re infected.”
He suggests that due to this emerging data, cancer survivors might benefit from increasing precautions against respiratory viruses, including vaccination when feasible.
During an interview with CPR News health reporter John Daley, DeGregori elaborated on their research journey.
He recounted that the endeavor began during the pandemic when their team was interested in understanding the processes surrounding cancer dormancy.
By collaborating with colleagues from Albert Einstein College of Medicine, they sought to explore the impact of aging on dormant cancer cells.
DeGregori provided insight into the risk of cancer relapse, particularly for diseases like breast cancer, which might not manifest for years after initial remission.
He describes dormant cancer cells as akin to “sleeper cells,” lying in wait for a trigger to prompt their progression towards metastatic disease.
The research team was motivated by earlier studies indicating inflammation’s role in the activation of dormant cancer cells.
They hypothesized that respiratory viral infections, known to induce inflammation, could serve as a catalyst for this awakening.
The dichotomy of their research is further enriched by the combination of experimental evidence from animal models alongside epidemiological data from human studies.
As DeGregori explained, “If you only have the human studies, it’s correlative and it’s harder to draw a cause-and-effect relationship,” signifying the strength provided by the dual approach.
The team found substantiating data regarding how two studies confirmed heightened risks for cancer survivors infected with COVID-19, reinforcing their hypothesis linking respiratory viruses to cancer resurgence.
As DeGregori elaborated on the significance of using inflammation as a common feature linking smoking to cancer cell awakening, he cautioned against downplaying the implications of their discoveries.
“Given the sheer number of people that have been infected that have gotten COVID-19… this wasn’t an increased risk for people to get infected,” he remarked about the necessity of understanding the long-term ramifications of common respiratory infections.
When probed about the actual link to cancer-related deaths, DeGregori noted a lack of explicit signals in total cancer mortality data.
He suggested that this might be attributed to a constrained population of those affected by COVID-19, alongside other external factors related to healthcare accessibility during the pandemic.
Focusing primarily on cancer patients who previously battled cancer provided more measurable data outcomes in assessing risk associated specifically with COVID-19 infection.
The implications of their research findings point towards a need for heightened awareness concerning the associated risks respiratory viruses pose, particularly for cancer survivors.
According to DeGregori, it reveals the necessity for ongoing investigation into respiratory infections beyond their immediate effects.
As he articulated, “We need to continue to be very concerned about that next big COVID-19 type infection, whether it’s another coronavirus or some other virus.”
The call for primary prevention reaffirms the importance of vaccination and risk reduction, particularly for populations with prior cancer diagnoses.
DeGregori expounded upon the potential application of the findings, indicating that the clinical implications may affect various cancer types, even though their experimental focus was largely on breast cancer.
The ongoing work will dive deeper into the mechanisms involved, concentrating on IL-6’s role while elucidating how the immune system engages with growing cancer cells during infections.
Despite the exciting discoveries, DeGregori underscored the need for further experimentation before clinical recommendations could be fully established.
“Knowledge is power,” DeGregori remarked, emphasizing that understanding risks allows cancer survivors to make informed decisions regarding their health moving forward.
He acknowledged the challenges posed by funding cuts to research, critical for continuing this pivotal work, particularly with proposals suggesting significant reductions to the NIH budget.
Such cuts could threaten emerging research, especially for junior scientists beginning their careers in oncology.
“Our investment in research has made America a global leader in science and technology,” concluded DeGregori, voicing his concern for the potential adverse effects these budget constraints could impose on scientific progress.
Federal funding supported some of this groundbreaking research, including from a VA merit award and other philanthropic sources, allowing rapid exploration of this crucial subject matter.
The partnership between the Colorado research team and their collaborators spans institutions like Montefiore Einstein Comprehensive Cancer Center in New York and Utrecht University in the Netherlands.
As they seek to deepen the understanding of these complex interactions between respiratory viruses and dormant cancer cells, DeGregori and his team emphasize the need for coherent research strategies and sufficient funding to continue making meaningful advancements in cancer care.
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