Scientists Find Hidden Immune Cells That Kill Lung Cancer

Scientists at Australia's Walter and Eliza Hall Institute have found immune cells hiding in plain sight that can recognize and kill the most aggressive form of lung cancer.

The discovery centers on gamma delta T cells, a type of immune cell previously overlooked in small cell lung cancer research. These specialized cells can detect tumors even when the cancer has made itself invisible to conventional immune defenses, solving a puzzle that has stumped doctors for decades.

Small cell lung cancer claims lives faster than almost any other cancer, with fewer than 7 out of 100 patients surviving five years. Current immunotherapy treatments work brilliantly for some cancers but help only a rare handful of small cell lung cancer patients because these tumors are exceptionally good at hiding from the immune system.

Professor Kate Sutherland, who led the study published in Cancer Cell, said the findings answer a critical question about why so few lung cancer patients respond to immunotherapy. When her team analyzed tumor samples from patients, they found something remarkable: people whose tumors contained higher levels of gamma delta T cells lived longer.

To test whether these cells could actually fight cancer, researchers created miniature tumors in the lab using patient samples. They combined these mini tumors with gamma delta T cells taken from the same patients' blood and watched as the immune cells recognized and killed the cancer cells with striking effectiveness.

The team then discovered something even more promising. Two existing drugs, tarlatamab (already approved for small cell lung cancer) and zoledronate (used for osteoporosis), could supercharge these immune cells. Zoledronate increased the number of gamma delta T cells and enhanced their ability to spot tumors, while tarlatamab acted like a magnet, pulling the immune cells closer to cancer cells.

The Ripple Effect

The discovery emerged from analyzing data from two landmark clinical trials that changed how doctors treat small cell lung cancer. Using advanced genomic analysis, researchers connected strong gamma delta T cell activity to patients who benefited most from immunotherapy.

Dr. Jin Ng, who authored the study, said the findings open doors to personalized treatment approaches. For patients with lower levels of these immune cells, drugs like zoledronate could boost their natural defenses. Because therapies that grow and reinfuse gamma delta T cells already exist for other conditions, doctors might be able to quickly adapt them for lung cancer patients.

The research team is now working to translate these findings into new immunotherapy drugs specifically designed for small cell lung cancer, a disease that has seen frustratingly few treatment advances in recent decades.

After years of this cancer outsmarting medicine, doctors finally have a promising new weapon in the fight.