Genetically-altered immune cells attack cancer
Friday, 01 Sep 2006 10:31
Immune cells altered to target cancer
Science In Focus
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Normal immune cells have been genetically altered to be able to successfully target cancer tumours, US scientists claim.
According to researchers from the National Cancer Institute in the US, it is the first time that it has been demonstrated that engineered cells can survive in the body and shrink large tumours in humans.
The experimental treatment was given to 17 patients with advanced melanoma, a type of skin cancer.
More than a year and a half after the therapy began, two of the group saw their tumours shrink and were declared clinically free of the disease.
Although the study was only conducted on this small group of people, the researchers believe that they can engineer similar immune cells in the laboratory to attack more common tumours such as lung, breast and liver cancers.
Stephen Simpson, senior editor of Science, the medical journal the study is published in, described the study as a piece of "significant work".
"This work marks an important next step in harnessing the power of our immune systems to fight cancer," he said.
Professor John Toy, medical director at Cancer Research UK, said that the study's results were "preliminary but promising".
"It's important to realise that we are not looking at a 'miracle cure' for all cancers. The study produced encouraging results but the treatment only helped two of the 17 patients who received it," he said.
"Gene therapy is certainly an experimental area of promise in cancer research. It is to be hoped that these results can be built upon and improved in melanoma and also reproduced in other types of cancer."
Previous experiments carried out by the researchers have attempted to find ways to boost T cells, a special type of immune cell that can recognise and 'attack' foreign cells such as those found in tumours.
But not all people with melanoma have these T cells which can fight tumours, leading the researchers to create 'tumour fighters' by removing T cells from people with advanced-stage melanoma, genetically-altering them to carry the receptor that recognizes melanoma cells, and then replacing them back in the patients' immune systems.
As well as the two people whose tumours shrunk noticeably, in 15 patients in the study the newly-engineered T cells showed signs of persistence for at least two months after treatment.
The researchers are now attempting to identify how to engineer the T cells to last for longer.