DNA variations linked to brain tumors

ROCHESTER, Minn., July 6 (UPI) -- Mayo Clinic and University of California-San Francisco medical researchers say they have found a connection between DNA alterations and brain cancer.

The scientists say they found a linkage between DNA variations on human chromosome 9 and aggressive brain cancer known as glioblastoma.

The study, conducted with different patient populations at each institution, looked for genome-wide associations. The researchers said they found that people with the specific DNA alterations -- also known as single nucleotide polymorphisms -- have a 50 percent higher relative risk of developing glioblastoma.

"This is not to cause those who possess these SNPs to worry about having CT scans every year," said Dr. Robert Jenkins, senior author of the study. "Increased relative risk is just that -- relative." Jenkins said a normal person's risk of developing a glioblastoma is about 1 in 10,000, while those with one of the SNPs have about a 1 in 7,000 risk.

The scientists said glioblastomas are one of the most aggressive forms of brain tumor, with those who are diagnosed seldom living beyond five years.

The findings are reported in the online edition of the journal Nature Genetics.