Specific tumor cells may inhibit body's immune response to cancer

By Paul Basilio, MDLinx
Published February 9, 2017

Key Takeaways

Scientists in Canada have discovered a distinct cell population in tumors that inhibits the body’s immune response to fight cancer, according to a study published in the journal Nature Medicine.

These findings offer a critical insight into why some patients do or do not respond to immune therapies, according to principal investigator Pamela Ohashi, PhD, FRSC, director of the Tumour Immunotherapy Program, Princess Margaret Cancer Centre, Toronto.

The researchers, along with an international team of collaborators, analyzed more than 100 patient samples from ovarian and other cancer types to discover a distinct population of cells found in some tumors. This population of cells suppresses the growth of cancer-fighting immune cells and limits the ability of the immune system to fight off cancer.

“We’ve uncovered a potential new approach to modulate the immune response to cancer,” said Dr. Ohashi. “By looking at tumor biology from this different perspective, we will have a better understanding of the barriers that prevent a strong immune response. This can help advance drug development to target these barriers.”

In the future, Dr. Ohashi envisions a new era of combined therapies that simultaneously target and kill these suppressive cells while augmenting the immune response against cancer. These new tools have the potential to strengthen the way clinicians can treat cancer with immune therapy.

The team’s next research focus is to identify a biomarker for this distinct suppressive cell elsewhere in the body. This has the potential to provide a first-of-its-kind predictive clinical tool to determine when these cells are present in patients.

“That knowledge will guide clinical decisions to personalize cancer treatment to unleash an individual’s immune response,” Dr. Ohashi explained. “We need to identify ways to track these cells and find another source and ways to grow these cells for further study.”

Dr. Ohashi’s team has spent years studying tumor-infiltrating lymphocytes (TILs), a type of cell known to kill cancer cells. Patients with TILs often have better outcomes because they already have cancer-fighting cells in their tumors.

To  read more about the Tumor Immunotherapy Program, go to http://www.pm-immunotherapyprogram.ca/

The research was funded by the Canadian Institutes of Health Research and The Princess Margaret Cancer Foundation.

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