Gene editing could help fight cancer

Altering certain cells within a tumour could help the immune system fight cancer, a new study has shown.

Funded by Cancer Research UK and published in Cancer Research, the study has found a way to allow the immune system to attack tumour. Normally, the immune system is the body's natural defence against illness, but cancer can 'switch off' immune cells within a tumour, effectively hiding from the body's immune system.

Known as the PD-1 switch, it is usually a kind of safety device that prevents the immune system from attacking healthy cells. In the case of cancer, the switch is turned off, essentially tricking the body into thinking it doesn't need to fight back.

With this new discovery, scientists may have found a way to allow the immune system to work against the tumour with gene editing.

Led by Professor Karl Peggs and Dr Sergio Quezada, the team from University College London's Cancer Institute used a gene editing technique to remove PD-1 from the tumour. Tested on mice, the procedure allowed the immune system to tackle the cancer cells and shrink the tumour.

The process now needs to be trialled in a clinical setting to assess whether it could be used to treat patients.

This is not the first time a way has been found to get the immune system to tackle cancerous tumours. Previously, drugs called checkpoint inhibitors have been used to prevent tumours from flicking the 'off' switch. However, these drugs affect the whole immune system as opposed to specifically tackling the tumour, which means some patients experience pronounced side effects. 

"This is an exciting discovery and means we may have a way to get around cancer's defences while only targeting the immune cells that recognise the cancer," said Dr Quezada, Cancer Research UK scientist and co-lead author from University College London's Cancer Institute.

"While drugs that block PD-1 do show promise, this method only knocks out PD-1 on the T cells that can find the tumour which could mean fewer side effects for patients," he added.