Could Inflammation Elsewhere In The Body Help Breast Cancer Return? A Study Offers Clues
Finishing breast cancer treatment can feel like reaching the other side of a long journey. But for some people, the uncertainty continues.
Breast cancer cells can remain hidden in the body for years before becoming active again. These dormant cells can lie quietly without forming tumors or causing symptoms. So what wakes them up?
A new study in mice1 explores how inflammation in one part of the body could affect these cancer cells.
About the study
Breast cancer cells can sometimes spread to the bones and remain inactive for years. Researchers wanted to understand what might cause them to start growing again.
To investigate, the team built an artificial bone structure in mice using early bone-forming cells from newborn mice. The structure had its own bone marrow, blood vessels, and immune cells, mimicking real bone.
After introducing breast cancer cells to the artificial bones, most became dormant instead of growing. The researchers also studied human breast cancer cells and bone samples from eight patients to see whether their findings might apply to humans.
Gut inflammation may wake dormant cancer cells
When researchers triggered inflammation in the mice's intestines, dormant cancer cells in the mice's bones began growing again. The longer the inflammation lasted, the stronger the effect.
The team then tested whether this activity could lead to tumors. They injected breast cancer cells directly into the mice's shin bones and triggered gut inflammation. Tumors developed in 80% of mice with inflammation, compared to 30% of those without it. This increase was eliminated when the researchers used a drug to block the inflammation.
Researchers identified a possible explanation for this that involves HMGB2, a protein released by immune cells during inflammation. Mice engineered to produce extra HMGB2 in their bone tissue developed more tumors, even without gut inflammation. The team also found the protein in human bone samples containing breast cancer cells, suggesting a similar process may occur in humans.
What this could mean for late breast cancer recurrence
Previous research has linked breast cancer cells found in bone marrow before surgery to a higher risk of recurrence. These findings offer a possible clue as to why breast cancer can return years after treatment.
However, this study doesn't prove that inflammation triggers cancer recurrence in people. Most of the research was conducted in mice, and injecting cancer cells directly into bone can cause inflammation of its own. Further studies are needed to determine whether this process contributes to late recurrence in humans.
What breast cancer survivors should know
If you've had breast cancer, this research isn't a reason to worry about every bout of inflammation. The study focused on a specific form of induced gut inflammation in mice and doesn't show that everyday inflammation increases recurrence risk in people.
For now, follow the care plan recommended by your oncology team. If you have an inflammatory condition, such as inflammatory bowel disease, work with your health care providers to manage it. This study doesn't show that treating inflammation prevents cancer from returning in humans, but managing an existing condition remains important for your overall health.
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The takeaway
This research offers a plausible explanation for how inflammation may help dormant breast cancer cells in bone start growing again—an early step toward understanding late recurrence.
It is an exciting development, but it can't be applied to human treatment just yet. Until researchers have more answers, recommended follow-up care remains the priority for breast cancer survivors.