Understanding how immune cells around the brain protect childhood ependymoma tumours

Childhood ependymoma is a rare and aggressive type of brain and spinal cord cancer. It has a relatively low overall survival, and there is a lot to uncover to improve outcomes for these young patients. For example, we don’t know much about how the immune system behaves or where it comes from in children’s brain tumours.

Dr Elizabeth Cooper’s research proposes that immune cells within childhood brain tumours come from the bone marrow in the skull. This has a unique role in helping tumours avoid being killed by the immune system. Like the bone marrow in other parts of the body, the skull bone marrow contains cells called haematopoietic stem cells (HSCs). These HSCs produce most of our body’s immune cells. The HSCs normally stay in the bones until they become mature immune cells and can protect the body. However, Dr Cooper’s research team have identified a group of HSCs that leave the skull bone marrow too early and travel into the tumour.

This research project, based at the University of Cambridge, aims to understand why these cells move from the skull into the tumour, and how they help the tumour grow. The researchers have experimental evidence for how these HSCs could play a role in the fight against cancer. They believe that the HSCs collect waste released by brain cancer cells from the fluid around the brain (the cerebrospinal fluid). The HSCs can then use the waste to alert special immune cells called helper T-cells to threats. This interaction might help the T-cells recognise and hunt down the brain cancer cells.

However, brain tumours seem able to hijack this process, making T cells believe they are not a threat. Dr Cooper hopes to unravel how the HSCs that are supposed to protect the borders of the brain could be helping ependymoma survive. By understanding the role of these important immune cells in the tumour, the researchers may be able to find a way to encourage them to fight the cancer.