‘Immune profile’ may guide chemotherapy for breast cancer

April 4th, 2011 - 12:39 pm ICT by ANI  

Washington, Apr 4 (ANI): US researchers have discovered a new way to predict breast cancer survival based on an ‘immune profile’ - the relative levels of three types of immune cells within a tumor. Knowing a patient’s profile may one day help guide treatment.

The team at the University of California, San Francisco, showed that they could use drugs to alter this immune profile in mice.

Giving these drugs to mice, in combination with chemotherapy, significantly slowed tumor growth, blocked metastasis and helped mice live longer, suggesting that the approach may work in people.

Normally the immune system protects the body by unleashing on tumors an immune cell called a killer T cell. This cell is effective, but dangerous. It can shrink tumors, but it also can damage healthy tissue. So the immune system uses another type of immune cell, called a macrophage, to control killer T cells, calling them where needed and shutting them down to keep them from damaging healthy tissue.

Lisa Coussens and her colleagues found that some cancers subvert this process by using macrophages to suppress the killer T cells and keep them away from tumors.

This effect of this subversion was apparent in tumor biopsies the team examined from 677 people with breast cancer. An immune profile based on the relative abundance of three immune cells in the tumors - the killer T cell, the macrophage, and another immune cell known as a helper T cell - accurately predicted overall survival from the disease, determined whether an individual’s cancer was prone to metastasize, and predicted whether it would recur once treated. The tumors that tended to fare worse under the treatment had fewer killer T cells in them.

This basic observation is what led to the new treatment strategy, which the team tried first in mice. They used a drug to reprogram mouse tumors, changing their immune profiles and looking to see whether that made them more susceptible to chemotherapy. It did. When they next gave the mice chemotherapy, their tumors grew slower and the mice lived longer without metastasis.

A research article describing the discovery appears in the inaugural issue of the journal Cancer Discovery. (ANI)

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