Hormone Discovery Reveals Mechanism of Immune Suppression in Cancer Progression

Researchers at UT Southwestern Medical Center have uncovered how a specific hormone interacts with immune cell receptors to shield cancer cells from the body's immune defenses. The study, published in Nature Immunology, shows that this hormone binds to a receptor on myeloid immune cells, suppressing their ability to attack tumors. This interaction diminishes the recruitment and activation of cancer-fighting T cells, allowing tumors to grow unchecked.

The team identified a hormone called Secretogranin 2 (SCG2) as a key player in this process. Although its role in immune responses was previously unclear, laboratory experiments demonstrated that SCG2 binds to the receptor LILRB4 on myeloid cells, initiating a signaling pathway that inhibits their anti-tumor activity.

In mouse models engineered to express human LILRB4, tumors producing SCG2 grew rapidly. Conversely, blocking LILRB4 with specific antibodies or eliminating SCG2 from the system significantly slowed tumor growth. These findings suggest that the SCG2-LILRB4 interaction is a critical mechanism by which cancer evades immune surveillance.

The discovery opens potential avenues for developing novel immunotherapies targeting this pathway. By disrupting the SCG2 and LILRB4 interaction, it may be possible to enhance the ability of the immune system to combat cancer. Conversely, harnessing this pathway could also be explored for treating autoimmune and inflammatory diseases caused by overactive immune responses, an area that the researchers plan to investigate further.

This breakthrough provides a deeper understanding of immune evasion by tumors and highlights new targets for cancer treatment strategies.