Sekwon Jang, MD, is board certified in medical oncology, hematology and internal medicine. He serves as Inova’s director of Melanoma and Cutaneous Oncology Therapeutics and Research and director of quality at the Inova Schar Cancer Institute. He has a special interest in melanoma and other skin cancers. Read Dr. Jang’s profile.
Thomas P. Conrads, PhD, recently joined the Inova Schar Cancer Institute as associate director of scientific technologies. He specializes in translational cancer research, which aims to transform laboratory discoveries into innovative treatments for people with cancer. Read more about Dr. Conrads.
An exciting discovery is revealing new details about how the immune system can be harnessed to fight cancer. The research, conducted by an international team of scientists, was published March 3 in Science magazine. Inova cancer experts Thomas Conrads and Sekwon Jang weigh in on what the discovery means.
Dr. Thomas Conrads:
Fighting Cancer With The Immune System
The immune system’s job is to recognize and destroy harmful invaders such as viruses, bacteria and cancerous cells. To do that job, the immune system has evolved a magnificently complex set of tools for distinguishing normal cells from harmful ones. Among those tools are killer T-cells — a type of immune cell that identifies foreign invaders and targets them for destruction.
To do that, T-cells survey antigens, small fragments of proteins on the surface of a cell. If a virus or bacterium invades, for example, T-cells recognize these viral or bacterial protein fragments on its surface, marking it to be destroyed.
In a perfect world, that system works to destroy cancerous cells, too. As a cancerous tumor grows, it acquires mutations, or errors, in its genetic code. Those errors often result in abnormal proteins on the surface of the cancer cells. T-cells can recognize those changes in cancer cell proteins, allowing them to distinguish between normal and abnormal cells.
But that system doesn’t always work. Unfortunately, cancer cells are nefarious and don’t always play by the rules. One of the hallmarks of cancer is its ability to hide from T-cells to avoid detection and destruction by the immune system.
It’s no surprise, then, that researchers are working to find methods to prevent cancer cells from hiding from the immune system. Treatment that uses parts of a patient’s own immune system to fight cancer is known as cancer immunotherapy.
In the past few years, cancer immunotherapy drugs that aim to prevent cancer from hiding have been approved to treat melanoma, lung cancer and bladder cancer. But while the treatments are very effective in some patients, not all patients seem to respond to them.
The new research helps explain why. A tumor might contain millions of individual cancer cells. This research suggests that when those millions of cells all harbor the same core antigens, cancer patients fare better with immunotherapies.
Unfortunately, it is often the case that a tumor has many different subtypes of cells that have different sets of antigens. While more research is needed in more tumor types, this study suggests that these patients may not respond as well to immunotherapy drugs.
Dr. Sekwon Jang:
Red Flags for Treatment
This new study brings researchers one step closer to creating personalized vaccines that could take out tumors at their root by targeting core antigens. But the study also raises some red flags for physicians treating cancer.
Doctors often use chemotherapy and radiation therapy to treat cancer. But those treatments can trigger more mutations in surviving cancer cells. That could lead to a diverse population of cancer cells with different sets of antigens. For patients who have already been treated with those therapies, it’s possible that immunotherapy might be less effective.
This is a very important issue for researchers to study further to optimize the timing of immunotherapy.
Studies such as this one are important for moving cancer treatment toward a more targeted, personalized approach. As leaders in personalized medicine, the doctors and researchers at the Inova Schar Cancer Institute and the Inova Translational Medicine Institute are committed to better understanding, predicting, preventing and eliminating cancer.