University of Minnesota researchers have discovered a single human enzyme that they say is a major source of cancer-causing DNA mutations.
The enzyme, called APOBEC3B, is present in low levels in most healthy tissues. Its primary function is to protect cells from dangerous viruses. But U of M researchers have discovered that the enzyme can also be harmful.
They found significantly elevated levels of the antiviral protein in a half dozen types of cancer, including cancer of the breast, bladder, cervix, head, neck and lungs. They also found that mutation patterns in those cancers matched unique marks associated with the enzyme.
Professor Reuben Harris, who led the study, says the enzyme may be a greater source of cancer-causing mutations than UV rays from the sun and chemicals from smoking. Harris hopes to find a way to block the enzyme from mutating DNA, just as sunscreen blocks mutations that lead to melanoma.