Scientists in the United States have found a small change in human genes that may explain why people are more likely to get certain types of cancer compared to other primates. This discovery may help in creating better treatments, especially for solid tumours that are hard to treat with current methods.
Researchers from the University of California, Davis studied a protein called Fas Ligand, which is used by immune cells to kill cancer cells. In humans, this protein has a tiny difference — a change in just one amino acid — which makes it easier for a cancer-related enzyme called plasmin to break it. Once Fas Ligand is broken, the immune cells cannot use it properly to kill cancer cells.
This problem does not happen in non-human primates like chimpanzees, where Fas Ligand is stronger and not easily affected by plasmin. The study was published in the journal Nature Communications.
Plasmin is found in high levels around many solid tumours like breast, colon and ovarian cancers. So, even when the human immune system is ready to fight, the tumour can block one of its key weapons. This may be one reason why immune-based treatments like CAR-T cell therapy work well for blood cancers, but not for solid tumours.
The good news is that scientists found ways to protect Fas Ligand from plasmin. By blocking plasmin or making Fas Ligand stronger, the immune system can once again kill cancer cells. This opens up new ideas for improving cancer treatments by combining them with plasmin-blocking drugs or special antibodies.
The study also points to a possible link between this gene change and the evolution of humans. While it may have helped with brain development, it seems to have made people more vulnerable to certain cancers. The research shows how learning from other primates can help us understand cancer better and find new ways to treat it.
