The link between stress and cancer has been known (or supposed) for many years, but specific evidence has been spotty. A new study by researchers at Yale University and reported in Nature magazine, probed the causes of cancer related to two genes (RAS and scribble), and discovered two not so good pieces of news: Cancerous growth can be triggered by mutations in more than cell, and stress is a major factor in making this happen.
The two genes are well known for their relationship to cancer. Some 30% of cancers involve the RAS gene. The scribble gene is responsible for tumor suppressing proteins, but when mutated, fails to suppress tumors. The researchers found in experiments with fruit flies (Drosophila melanogaster) that mutation in either gene was not enough to cause cancer; both genes had to mutate. However, what they found was something scientists had not previously known – the mutations do not need to occur within the same cell. Mutations to either RAS or scribble genes in nearby cells could combine to trigger malignant tumors.
The research also discovered that, loosely termed, ‘environmental stress’ was a factor in facilitating the communication between mutated genes and thus enabling the cancerous growth. The mechanism is involved with the so called JNK pathway (a protein kinase reaction), a signaling pathway between cells that is often produced by trauma (wounds, tears, infections) to body tissue.
“The bad news is that it is much easier for a tissue to accumulate mutations in different cells than in the same cell,” says Tian Xu, who also is a researcher with the Yale Cancer Center and the Fudan-Yale Center for Biomedical Research at Fudan University in China.
“A lot of different conditions can trigger stress signaling: physical stress, emotional stress, infections, inflammation—all these things. Another bad news for cancer,” Xu says.
The good news from the research focuses on the JNK signaling pathway, which is potentially susceptible to blockage. Although cancer can still be triggered in single cells, and not all cancers can be triggered by neighboring cell mutations, at least some kinds of cancer (and especially under some conditions, like those where people are undergoing unusual stress) might be prevented by blocking JNK signaling.