A research team led by Associate Professor Scott Byrne based at The University of Sydney has discovered a vital mechanism that shows how cells in the immune system are hijacked by ultraviolet (UV) exposure, causing them to suppress immunity and help tumour development. Their findings could lead to a new treatment for aggressive skin cancers such as squamous cell carcinoma.
Australia has one of the highest skin cancer rates in the world, with more than two-thirds of Australians developing one of the various forms of skin cancer at some point in their lives. Avoiding excessive UV exposure is recommended by many health organisations, but we do not yet know by how much this exposure needs to be reduced to truly prevent cancer. Even though we all know that UV exposure can lead to cancer, the specific mechanisms for that remain unknown. Researchers need a thorough understanding of UV exposure’s impact on cells to devise new interventions for this common disease.
Associate Professor Byrne and his team have discovered that UV exposure causes some immune cells, called B cells, to actively participate in the development of skin cancer. These B cells normally protect us from infection, but under the influence of sunlight, some of them can start producing immunity-suppressing compounds.
The team has discovered that targeting these rogue, sunlight-activated B cells with an antibody can treat existing skin cancer tumours in mice.
In an exciting development, there are already drugs on the market that target B cells in a similar way.
The team also found that UV exposure on the skin causes lymph nodes to accumulate skin-derived microparticles. Future research will investigate whether this might be one of the mechanisms by which UV exposure suppresses the immune system.
The high incidence of skin cancer in Australia makes it a significant health and economic burden. The need for better treatments is especially urgent for patients with UV-induced squamous cell carcinoma, which can be aggressive and may quickly spread elsewhere in the body.
With more detailed knowledge of the specific molecular mechanisms that lead from UV exposure to cancer, researchers will potentially be able to develop better strategies for the prevention and treatment of skin cancers. A promising avenue is the potential to use existing drugs to target the newly discovered pathway.
Associate Professor Scott Byrne The University of Sydney