Thousands of breast cancer patients have been given hope after scientists found an immune cell which may stop the disease returning.
In a world-first discovery, researchers have spotted ‘gamma delta T cells’ in human breast tissue.
They believe the cell, released by the immune system to fight tumours, may play an important role in wiping out breast cancer.
Women are more likely to survive breast cancer if their immune system kills all the tumour cells so the cancer cannot come back.
Experts at the Francis Crick Institute and King’s College London looked at 11 women with triple negative breast cancer, the most deadly type.
Those with greater numbers of gamma delta T cells in their tumours were alive four years later.
Scientists have discovered a new immune cell which could stop breast cancer returning (file)
But five of those with a low number of the vital cells died, after their cancer returned.
The breakthrough opens the doors for future treatments which could see sufferers injected with extra gamma delta T cells taken from healthy donors.
The cells are thought to be released by the immune system after changes in breast tissue.
They have previously been spotted in the gut and skin, but this is the first time they have been identified in the breast.
Lead author Dr Fernanda Kyle-Cezar, at KCL, said: ‘Proving that these special cells are present in human breast tissue is an exciting first.
‘We knew from animal model studies that gamma delta cells might play an important role in killing tumours.’
She added: ‘But this is the first clear evidence that they may do so in human breast cancer.
‘The discovery opens the door to look at new ways we may be able to tackle this devastating disease.’
The scientists first spotted the gamma delta T cell after examining tissue from 90 patients and counting the cells using their DNA.
They then tested how different levels of the specialist cell affected the survival chances of women with triple-negative breast cancer.
Figures show around half of women diagnosed with the killer form of the disease see their cancer come back within five years.
The study, published in the journal Science Translational Medicine, tracked 11 women from Guy’s and St Thomas’ Hospital Trust in London.
It found five women recovered from breast cancer and were still in the clear four to five years later.
In every case, these women had higher levels of gamma delta T cells in their tumours compared to their normal breast.
The other six patients saw their cancer come back within 18 months and kill them. All but one patient in this group had low levels of gamma delta T cells.
There are around 55,000 new cases of breast cancer diagnosed each year in the UK, and roughly 268,600 in the US. Around 15 per cent of these are triple negative.
The aggressive form of the cancer does not respond to hormone therapies, such as Tamoxifen.
It means scientists seeking a way of helping patients have had to look for alternative immunotherapy treatments.
Co-author Dr Yin Wu, a clinician at Guy’s and St Thomas’ Hospital and University College Hospital, said the findings may lead to new immunotherapy treatments.
She said: ‘It could mean that in the future we’re able to improve a patient’s chance of survival by either artificially activating more of these cells to fight the tumour cells or we could transfer cells from a donor.’
Experts believe gamma T cells are better at detecting cancer than the body’s more common white blood cells, T cells.
Cancer cells are able to hide from white blood cells by adapting to change the types of proteins they emit.
Gamma delta cells are thought to overcome this problem by detecting unhealthy changes in breast tissue.
They then recruit the T cells to attack, while also killing and damaging cancer cells themselves.
Dr Iain Foulkes, from Cancer Research UK, which part-funded the study, said: ‘Treatments that harness the power of the body’s own immune system hold great promise for the future of cancer medicine and are already making a real difference for people with some types of cancer.’