Tumor recurrences are a horror for anyone who has had cancer before. Renewed growth is one of the leading causes of death in cancer patients, and no one really knew what caused this relapse.
At the Wistar Institute in Philadelphia, new findings have now emerged that strongly suggest that stress reactivates cancer.
Stressed mice developed cancer again after treatment
The American researchers studied the effects of stress-related immune reactions on tumor growth. To do this, they caused lung cancer in mice and treated the animals with surgery and medication until they appeared to be healthy again.
Then they stressed some of the animals, while the rest remained undisturbed. It only took three weeks for all stressed animals to show new tumors – the other, non-stressed animals, however, remained cancer-free.
These two proteins are to blame for tumor growth again
The scientists examined the blood of the test animals and found significantly increased levels of two proteins in the stress mice: S100A8 and S100A9 are released by the neutrophils, immune cells that respond to stress.
Six animals were unable to produce these proteins in the first place; only one of them developed a tumor recurrence. The researchers also met old friends, S100A8, and S100A9, in the blood of former lung cancer patients.
35 subjects had elevated values, and within 33 months cancer returned in 11 of these patients. 45 had low protein levels and only 6 of them relapsed during the same period. 31.4 versus 13.3 percent: That looks like a significant difference.
Beta-blockers to prevent tumor recurrence?
Beta-blockers reduce the physical effects of stress and could therefore help prevent relapses. In another attempt, mice were given appropriate drugs and promptly developed fewer tumors despite the stressful circumstances.
Clinical observations have long suggested that lung cancer patients have a longer lifespan if they take beta-blockers. There is also increasing evidence of this connection in other types of cancer.