Environmental factors, such as exposure to the sun. Conditions such as psoriasis - a chronic, autoimmune skin disease closely associated with a similar region of the genome. Exposure to viruses. Follicular lymphoma is associated with HIV infection, occurring in as many as 10 percent of all HIV-positive patients, according to the Lymphoma Research Foundation.

The genome-wide association study was conducted using DNA from a population-based non-Hodgkin lymphoma case-control study in the San Francisco Bay Area led by UC San Francisco researchers. Follow-up validation studies were done using independent case-control studies from Canada and Germany.

To reduce the potential for complicating factors, the more than 3,000 samples in the UC Berkeley-TGen study were from individuals who were HIV negative. Dr. Brown said future studies could include HIV-positive individuals, if enough samples were made available.

This pooled genome-wide association study used by the UC Berkeley-TGen investigators allowed them to screen more than 500,000 SNPs. The nearly 90 most significant SNPs were then genotyped to more closely examine their association with lymphoma.

This same pooling technique has been pioneered by TGen to screen for genes in other studies. Additional collaborations between UC Berkeley and TGen are planned.

"This study paves the way for more in-depth research into this type of cancer, which is increasingly affecting more people,'' said Dr. Jeffrey Trent, TGen's President and Research Director. "This study also builds an important collaborative relationship between TGen and UC Berkeley, one of the nation's top universities.''

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