Investigating biomarkers of response to immunotherapy in small cell lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Small cell lung cancer (SCLC) is a rare fast-growing lung cancer. It occurs when healthy cells in the lungs mutate or change into cancerous cells. Anyone can get this type of cancer, but it typically affects people who have a long history of smoking tobacco. It is the most aggressive form of lung cancer, where less than 7 percent of people with the disease live longer than 5 years. This needs to be drastically improved.

Long-lasting survival benefits of immunotherapy, a type of treatment where the immune system is used to fight cancer, are only seen in a handful of small cell lung cancer patients, with most gaining no benefit. This highlights the urgent need for new therapeutic approaches to improve health outcomes and save lives. Using advanced technologies, we studied the features of hundreds of individual immune cells from small cell lung cancer samples donated by patients. We found a special type of immune cell called “gamma delta T cells” in the small cell lung cancers. Gamma delta T cells are like the body’s defenders – they are cells that can kill foreign invaders and cancer cells. In our laboratory experiments, we showed that gamma delta T cells can kill small cell lung cancer cells.

We also looked at samples from patients with small cell lung cancer enrolled in clinical trials. People who had high levels of gamma delta T cells their tumours responded better to immunotherapy. With this research, we want to confirm that having more gamma delta T cells in tumours is linked to a better response to immunotherapy for small cell lung cancer patients.