Myeloid Cells and Cancer: A New Understanding

Myeloid cells are among the first immune cells recruited to attack tumors, but these cancer-fighting cells quickly convert to support tumor growth. Recent studies indicate that receptors on these cells interact with certain hormones, leading to the suppression of the immune system.

Challenges Facing Current Immunotherapies

Despite significant advances in immunotherapies such as immune checkpoint inhibitors, their effectiveness is limited to only 20% to 30% of cancer patients. This suggests that tumors employ various methods to evade immune system attacks.

Research conducted by Cheng Cheng “Alec” Zhang’s laboratories has shown that myeloid immune cells contain inhibitory receptors known as LILRB4. It has been found that stimulating this receptor prevents myeloid cells from attacking tumors.

Discovery of SCG2 Hormone and Its Impact on Myeloid Cells

Researchers conducted a comprehensive genomic screening to search for proteins that might interact with LILRB4. The result was the discovery of a hormone called SCG2. Although previous research suggested that SCG2 plays a role in immune response, its function and future were unknown.

Laboratory experiments confirmed that SCG2 interacts with LILRB4, leading to the disabling of the immune capabilities of myeloid cells and preventing them from recruiting T cells to fight tumors.

Mouse Experiments and Future Applications

In experiments conducted on genetically modified mice expressing the human form of LILRB4, tumors grew rapidly when injected with SCG2-producing cancer cells. However, treating these mice with antibodies that block LILRB4 significantly slowed cancer growth, as did the removal of SCG2 from their bodies.

These experiments suggest that the interaction between LILRB4 and SCG2 allows cancer to grow unimpeded by myeloid and T cells, and possibly other types of immune cells.

Conclusion

This study represents an important step in understanding how myeloid immune cells transition from fighting cancer to supporting it. Understanding the interaction between LILRB4 and SCG2 opens new avenues for developing immunotherapies targeting this interaction, potentially offering a new solution for combating cancer. At the same time, providing additional amounts of SCG2 could be a promising therapeutic approach for autoimmune or inflammatory disorders caused by myeloid cells. Researchers plan to continue exploring these possibilities in the future.