A vaccine to help patients fend off blood cancers could be a reality in the near future.
Scientists are looking at treating many types of cancer with vaccines
It could even be given to healthy people who donate bone marrow to treat patients with multiple myeloma.
Scientists have been testing candidate jabs in humans and say early results are promising.
These use specially-treated material from the patient's cancer to try to encourage the body's own immune system to pick out and attack myeloma cells.
Myeloma develops from cells within the bone marrow called plasma cells, which produce proteins called antibodies to help to fight infection.
In myeloma, a single plasma cell develops faults and multiplies out of control, producing excessive amounts of a single type of antibody.
It affects approximately 3,500 people in the UK each year, and is notoriously difficult to treat.
Even with chemotherapy and a bone marrow transplant, the average patient will live for only two to four years, meaning new treatments are urgently needed.
For the last four years, researchers from the National Cancer Institute in the US have been testing a trial vaccine in myeloma patients and healthy people donating bone marrow to these patients.
Researcher Dr Michael Bishop from the NCI's campus in Bethesda, Maryland, said: "With conventional bone marrow transplants you are transferring a new, healthy immune system to the patients with myeloma, and this new immune system is capable of recognising myeloma and attacking it.
"But this can be a relatively haphazard event.
"By giving the vaccine to the donor, they can build up immunity to the cancer.
"They will have this memory, so when the transplanted bone marrow cells come into contact with myeloma they will attack it."
Past research has already shown that giving the vaccine to the patient boosts their immune system.
Dr Bishop said it was a controversial idea to vaccinate healthy donors, but that was entirely safe.
"The protein the vaccine is based on is a byproduct of the cancer. It does not give you cancer.
"There is no risk to the donor, other than those related to any vaccine."
He said the beauty of the treatment was that it would only attack the myeloma cells and would not harm healthy cells because its target was so specific.
He said it might be possible to treat other cancers with similarly unique targets, such as some forms of lymphoma, in the same way.
"We are very pleased with initial results."
He hopes it will be available as a treatment in coming years.
A spokesman from the Leukaemia Research Fund said: "The concept is very attractive, but there are various hurdles to get over that affect both the donor and the patient.
"The big issue is whether it is ethically acceptable to vaccinate donors."
Professor Peter Johnson, of the Cancer Research UK cancer unit at Southampton General Hospital, said: "The reason we can ethically and reasonably do that is because this is a unique antigen [target] which is only present on malignant cells in the recipient marrow."