A US woman with advanced breast cancer is healthy again after taking part in an experimental treatment, using her body's own immune system to wipe out the tumours.
Judy Perkins, from Florida, had advanced breast cancer which had stopped responding to chemotherapy and other treatments.
"It feels miraculous and I am beyond amazed that I have now been free of cancer for two years," she told the media.
How they did it
Researchers took a small sample of Ms Perkins' tumour and studied the DNA mutations in it.
Then they extracted immune cells from the tumour and grew billions of them, finding those which would be the most effective to kill her cancer.
Study author Dr Steven A Rosenberg from the National Cancer Institute said the research was "experimental right now".
"But because this new approach to immunotherapy is dependent on mutations, not on cancer type, it is in a sense a blueprint we can use for the treatment of many types of cancer."
The patient was injected with 80 billion selected immune cells, as well as being given a drug called pembrolizumab or Keytruda, which can help the immune system to attack cancer.
"After the treatment, all of this patient's cancer disappeared and has not returned more than 22 months later," Dr Rosenberg said.
It is the first time this kind of approach has been successful in treating advanced breast cancer.
Immunotherapy drugs such as Keytruda are already widely used for other cancers, such as melanoma and increasingly lung cancer.
Second chance at life
Judy Perkins said she felt as if she had a second chance at life.
"About a week after the therapy, I started to feel something. I had a tumour in my chest I could feel shrinking," she said.
"I had given up fighting. After the treatment dissolved most of my tumours, I was able to go for a 40-mile hike."
Professor Frances Boyle, director of the Patricia Ritchie Centre for Cancer Care and Research at Sydney's Mater Hospital, who was not involved in the study, said the technique was able to produce a lasting effect.
"This is absolutely precision medicine. But it's not a drug. It's a technique done in a laboratory," she said.
"They were able to give the patient's own immune system a major boost."
Tom Misteli, Ph.D., from the US National Cancer Institute, said the results highlighted the power of immunotherapy.
"If confirmed in a larger study, it promises to further extend the reach of this T-cell therapy to a broader spectrum of cancers," he said.
The research has been published in the journal Nature Medicine.
Professor Boyle said several immunotherapy trials for triple negative breast cancer are about to start in Australia.
