New drugs being developed could help the body's immune system to destroy hidden cancer cells, a study has suggested.

Scientists at the University of Edinburgh revealed that a protein called Focal Adhesion Kinase (FAK) - which is often overproduced in tumours - enables cancer cells to avoid attacks by the immune system.

They said that by blocking FAK, they could find a way to help the immune system recognise the cancer and fight it.

This, in turn, could lead to a new use for FAK inhibitors - a class of drugs that stop FAK from working.

FAK usually sends signals to help healthy cells to grow and move around.

But the researchers discovered it plays a different role in cancer cells, changing the nature of the immune system so that it protects the cancer cells rather than destroying them.

The team, led by Dr Alan Serrels of the Edinburgh Cancer Research UK centre, then showed that using an experimental FAK inhibitor prevented this change in the immune system, allowing the cancer cells to be treated as a threat.

They said it is the first time that FAK inhibitors have been shown to influence the ability of the immune system to recognise cancer and their use could increase the effectiveness of existing immunotherapies by making cancer cells more visible to the immune system.

Dr Serrels said: "FAK is hi-jacked by cancer cells to protect them from the immune system.

"This exciting research reveals that by blocking FAK, we've now found a promising new way to help the immune system recognise the cancer and fight it.

"The drug in this study is already in early stage clinical trials and could potentially be an excellent complement to existing immunotherapy treatments.

"Because it works within tumour cells rather than influencing the immune cells directly, it could offer a way to reduce the side effects of treatments that harness the power of the immune system against cancer."

The research was carried out in mice with a form of skin cancer called squamous cell carcinoma but researchers said it is likely to also apply to other cancers. The results showed that tumours disappeared when the mice were given FAK inhibitors.

Nell Barrie, senior science communications manager at Cancer Research UK, said: "This promising research suggests these drugs may be able to help the immune system to destroy cancer cells.

"Research to maximise the power of the immune system is a really exciting area that Cancer Research UK scientists are exploring in detail.

"This particular approach hasn't yet been tested in people but there are plans to now find out how it could benefit patients alongside other immunotherapy treatments."

The research, published today in the journal Cell, was funded by Cancer Research UK, the European Research Council, and the Medical Research Council.