Many Elderly Found with Puzzling Mutations Linked to Leukemia, Lymphoma

Health and Medicine for Seniors

Many Elderly Found with Puzzling Mutations Linked to Leukemia, Lymphoma

Researchers find no connection with blood cancer that seldom strikes senior citizens

Oct. 22, 2014 A surprisingly large percentage 5 percent of senior citizens over age 70 have been found to have genetic mutations linked to leukemia and lymphoma in their blood cells. The vast majority won't get blood cancer, however, as the incidence of these cancers is less than 0.1 percent among the elderly, according to the researchers at Washington University School of Medicine in St. Louis.

Mutations in the body's cells randomly accumulate as part of the aging process, and most are harmless. For some people, genetic changes in blood cells can develop in genes that play roles in initiating leukemia and lymphoma even though such people don't have the blood cancers, the scientists reported Oct. 19 in Nature Medicine.

"But it's quite striking how many people over age 70 have these mutations," said senior author Li Ding, PhD, of The Genome Institute at Washington University. "The power of this study lies in the large number of people we screened. We don't yet know whether having one of these mutations causes a higher than normal risk of developing blood cancers. More research would be required to better understand that risk."

The researchers analyzed blood samples from 3,000 people enrolled in The Cancer Genome Atlas project, a massive endeavor funded by the National Cancer Institute and the National Human Genome Research Institute at the National Institutes of Health (NIH). The effort involves cataloguing the genetic errors involved in more than 20 types of cancers.

The patients whose blood was analyzed for the current study had been diagnosed with cancer but were not known to have leukemia, lymphoma or a blood disease.

They ranged in age from 10 to 90 at the time of diagnosis and had donated blood and tumor samples before starting cancer treatment. Therefore, any mutations identified by the researchers would not have been associated with chemotherapy or radiation therapy, which can damage cells' DNA.

The researchers, including Genome Institute scientists Mingchao Xie, Charles Lu, PhD, and Jiayin Wang, PhD, zeroed in on mutations that were present in the blood but not in tumor samples from the same patients. Such genetic changes in the blood would be associated with changes in stem cells that develop into blood cells, but not to the same patient's cancer.

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Many Elderly Found with Puzzling Mutations Linked to Leukemia, Lymphoma