According to the American cancer society, metastatic breast cancers or stage 4 breast cancers have 5-years survival rate of 22%, which is lower than at early stages.
Metastatic breast cancer is when cancer spread from its primary place at the breast to other parts of the body which makes it more difficult to treat and lowers the survival rate.
A new study published in Nature Cell Biology revealed that certain breast tumors could stop the growth of their secondary cancers. They discovered an ecosystem in which the primary breast tumor emits signals that freeze the growth of secondary tumors anywhere else in the body.
“This new research has yielded that rare thing a clue from the cancer itself about new possibilities to fight its spread,” says Dr. Christine Chaffer co-lead author of the study. “Our goal is to work out how we can mimic this ‘freezing’ of secondary cancers, so that one day we might influence all breast cancers to keep their secondary tumors in check.”
There are cells called Metastasis-initiating cancer cells (MICs) which are the cells that break away from the primary tumor to other parts of the body and start growing secondary tumors. The study shows that primary breast tumors can affect these ‘breakaway cells.’ The primary tumor emits signals via the immune system through an inflammatory response involving interleukin-1β (IL-1β). The immune cells invade the body trying to reach the sites where the MICs or breakaway cells have settled to grow new secondary tumors to freeze them and stop the tumor growth.
“When breakaway cells are forced to remain in the transition state, they don’t grow very well,” remarks Dr. Sandra McAllister, who co-led the research with Dr. Chaffer. “Their ability to form a new tumor is severely compromised. So, remarkably, by activating the immune response, the primary tumor essentially shuts down its own spread.”
These findings were observed in mice, but researchers say that there is evidence that this mechanism also occurs in humans. They found that breast cancer patients who are at risk of metastasis who had high levels of the same type of immune response had a better survival rate than those with low levels.
Dr. Chaffer explains that they are now trying to understand the signals involved to activate this immune response and how the immune cells target the secondary sites. She also thinks that there is a therapeutic opportunity to stop cancer from metastasizing.
Dr. Chaffer and her team are hoping that these new findings could help to stop metastasis in all breast cancers and try applying the results to other types of cancers as well.
Watch the video below from TED-Ed to learn more on cancer metastasis.