SEATTLE — Advanced DNA technology is helping researchers identify bone-marrow or stem-cell donors once thought unsuitable for cancer-fighting transplants.
Scientists at Fred Hutchinson Cancer Research Center and the University of Washington have discovered that certain genetic "mismatches" between donors and patients will not cause transplants to fail, as previously believed.
The discovery, reported in Thursday’s edition of The New England Journal of Medicine, could help save hundreds of patients a year who seek new bone marrow or stem cells to fight off leukemia or other cancers.
"By understanding that certain mismatches are very well tolerated, more patients can benefit from a lifesaving transplant," said Dr. Effie Petersdorf of the Hutchinson Center, who directed the research.
The researchers used DNA sequencing to determine the exact tissue type of 471 Hutchinson-center patients with chronic myelogenous leukemia who received bone marrow transplants from unrelated donors between 1985 and 2000.
Examining transplant failures, researchers found no higher a failure rate in patients with a single gene mismatch than those with perfectly matched marrow.
"It showed us a patient shouldn’t be denied a transplant because a perfectly matched donor can’t be found," Petersdorf said.
The Seattle Cancer Care Alliance — a collaboration of the Hutchinson center, the UW and Children’s Hospital and Regional Medical Center — is regularly using DNA technology to identify bone marrow and stem cell donors, Petersdorf said.
The DNA technology used in the Seattle study is based on the same principles used in crime analysis of blood and other cellular material. It examines the sequence of DNA, or genetic code, to determine whether a gene is a match or near-perfect match.
DNA in bone-marrow tissue or stem cells that transplant patients receive must be as closely matched as possible to their own genetic material so their immune systems won’t reject the transplants.
Such transplants are given so that new blood cells produced will not be diseased, as they are in leukemia patients.
At any given time, about 3,000 cancer patients worldwide are searching for unrelated bone marrow or stem cell donors.
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