This month, oncologist and author Siddhartha Mukherjee sat down with Oprah to talk about the newly expanded edition of The Emperor of All Maladies, his landmark biography of cancer. Among the reasons he pointed to for cancer’s rise in younger people: chronic inflammation, and its role in rousing “sleeper” cancer cells that have lain dormant in the body — sometimes for years — after initial treatment.
It’s a striking claim, and it’s also a real and growing area of published research. Here’s what the science actually shows, and why it matters for how we think about the role of practices like yoga in cancer care.
The cells that don’t die — they wait
When a primary tumor is treated, it’s possible for a small number of cancer cells to have already broken away and traveled to distant tissue — commonly the lungs, bone marrow, or liver — before ever being detected. Rather than dying or immediately forming new tumors, some of these cells enter a dormant state: non-dividing, clinically invisible, and capable of persisting for years or even decades. This dormancy is thought to explain why cancer can recur long after someone is told they’re in remission.
For a long time, what actually triggered these cells to “wake up” and start dividing again wasn’t well understood. Recent research points squarely at inflammation as one of the key switches.
What the research shows
A few studies stand out:
- Neutrophil extracellular traps. A 2018 study published in Science (Cold Spring Harbor Laboratory) found that inflammation in the lungs — from chronic disease or even smoke exposure, in mouse models — causes immune cells called neutrophils to release web-like structures loaded with enzymes. Those enzymes alter a protein in the surrounding tissue in a way that switches on growth signaling in nearby dormant cancer cells, pulling them out of dormancy.
- MIT, September 2025. Robert Weinberg’s lab at MIT published findings in PNAS showing that dormant cells don’t wake up on their own — the “wake-up call” comes from the inflamed tissue around them. In their model, inflammation shifted dormant cells out of a stable state and into active proliferation.
- Surgery itself. Somewhat unsettling: the surgery used to remove a primary tumor can generate enough systemic inflammation to awaken dormant cells elsewhere in the body. Follow-up research found that anti-inflammatory medication given around the time of surgery reduced this effect in mice, and retrospective clinical data associated perioperative anti-inflammatory use with lower early recurrence in breast cancer patients.
- Viral infection. A widely covered 2023 study in Nature found that both COVID-19 and influenza infection could wake dormant breast cancer cells in the lungs of mice — driving up to a 100-fold expansion into metastatic disease within two weeks, largely through the inflammatory signaling molecule IL-6. Human data in cancer survivors showed a similar pattern of elevated risk following infection.
Taken together, this is a meaningfully different story than “inflammation causes cancer.” It’s a more specific and, for people who’ve already been through treatment, more directly relevant one: unresolved or repeated inflammatory insults appear to be a real mechanism by which residual disease can reactivate.
Where yoga fits — and where the evidence actually is
This is where the science gets genuinely useful for people living beyond a cancer diagnosis, because managing chronic inflammation isn’t just a pharmaceutical question. It’s also a question of what the body is doing day to day, and there’s real, published evidence that yoga has a measurable effect on inflammatory activity — not as a metaphor, but through an identifiable biological pathway.
The vagus nerve is a direct brake on inflammation. Researchers have characterized what’s called the cholinergic anti-inflammatory pathway: the vagus nerve, the primary channel of the parasympathetic nervous system, releases a neurotransmitter that binds directly to immune cells and suppresses their release of inflammatory signaling molecules. In effect, parasympathetic tone isn’t just about feeling calm — it’s a real-time regulator of the immune system.
Vagal tone is measurable, and it correlates with outcomes. The standard way to gauge vagal activity is heart rate variability (HRV). In cancer research, higher HRV has been linked to better survival in pancreatic, colorectal, and ovarian cancer — and in at least one pancreatic cancer study, the relationship was statistically explained by lower inflammatory markers in patients with higher vagal tone.
Slow, breath-centered practice raises vagal tone. Extended-exhale pranayama and paced breathing are established ways to shift the body toward parasympathetic dominance. This isn’t a leap of logic specific to yoga — it’s measurable via HRV in a wide range of studies.
And in cancer survivors specifically, yoga has shown direct anti-inflammatory effects. A randomized controlled trial of Iyengar-based yoga in fatigued breast cancer survivors produced measurable decreases in IL-6, TNF-α, and IL-1β — the same inflammatory cytokines implicated in waking dormant cells — along with reduced inflammation-related gene expression. A separate six-month yoga study in breast cancer survivors found comparable reductions in inflammatory serum markers linked to recurrence risk.
What we’re not claiming
It would be easy — and wrong — to round this up into “yoga prevents cancer relapse.” The research doesn’t support that, and we won’t overstate it. The dormancy-and-inflammation research is still largely built on mouse models and early human cohort data, not large interventional trials proving that lowering inflammation prevents recurrence. And the yoga studies, while real and peer-reviewed, involve modest sample sizes.
What the evidence does support is more modest, and still meaningful: chronic, unresolved inflammation is implicated in cancer recurrence through a specific, published biological mechanism, and yoga is one of the few practices with direct evidence of lowering the same inflammatory markers involved in that mechanism — through a pathway (vagal/parasympathetic regulation) that’s biologically well characterized, not speculative.
For a program built specifically for people living with and beyond cancer, that’s not a marketing claim. It’s a reason to keep showing up on the mat.
Want to go deeper?
Hear Mukherjee’s full conversation: Oprah’s podcast — “The Alarming New Risks of Cancer Everyone Needs to Hear” or watch the video.
Read the research yourself:
- Neutrophil extracellular traps and dormant cell awakening — Science, 2018
- Inflammation and dormant cell reactivation — MIT/Weinberg Lab, PNAS, 2025
- Yoga’s effect on inflammatory markers in breast cancer survivors — randomized controlled trial
Learn the practice:
Explore yoga4cancer teacher training and find an oncology-certified y4c teacher near you — every y4c class is built specifically around the safety and physiology of cancer treatment and recovery, informed by research like this.
Sources: Science, 2018 · PNAS / MIT, Sept 2025 · Science Translational Medicine, 2018 · STAT News on perioperative NSAIDs · CU Anschutz on COVID/flu and dormant cells · Cholinergic anti-inflammatory pathway review · Vagal activity and survival in pancreatic cancer · Yoga RCT in fatigued breast cancer survivors · Six-month yoga study on inflammatory markers
