Calling Cells to Arms: Engaging the Immune System to Battle Cancer

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In this CancerSmart lecture, hosted by Dr. Max Gomez, medical oncologists from Memorial Sloan Kettering discussed the growing importance of immunotherapy as a cancer treatment. In contrast to therapies that focus directly on the tumor, this treatment enhances the power of the immune system so that it can recognize and eliminate cancer cells throughout the body.

The idea of enlisting the immune system to treat cancer has been around since the 1800s, when surgeon William Coley noticed that a patient’s tumors mysteriously disappeared after an infection. Unable to duplicate the result, immunotherapy remained on the laboratory shelf until 2011, when the first immune-boosting drug won FDA approval for the treatment of patients with metastatic melanoma. Since then, immunotherapy drugs have been approved to treat non-small cell lung cancer. Many have also shown activity against smoking-related tumors, including head and neck cancer, bladder cancer, kidney cancer, and Hodgkin’s lymphoma.

According to Dr. Jedd Wolchok of Memorial Sloan Kettering, proteins such as CTLA4 and PD1 act like molecular “brakes,” preventing the immune system from becoming hyperactivated. The new immunotherapy drugs use monoclonal antibodies to temporarily release these brakes, permitting the immune system to respond more vigorously.

But some cancer cells find ways to evade the immune system altogether. That’s where medical oncologist Renier Brentjens comes in: he described his lab’s method of inserting genetic instructions into immune system cells known as T cells, enabling them to see and attack cancer cells that have been hiding in plain sight.

Physician-scientist Timothy Chan added that doctors are looking more closely at individual genetic mutations that make some people respond better than others to immunotherapy. This information may help doctors identify patients who may respond to immunotherapy alone, and those who may need a combination of therapies to eliminate their tumors and prevent them from returning.