September 9, 2024- About 8 to 10 million Americans over age 40 have an overabundance of cloned white blood cells, or lymphocytes, that hamper their immune systems. Although many who have this condition — called monoclonal B-cell lymphocytosis (MBL) — do not experience any symptoms, a new study shows they may have an elevated risk for several health complications, including melanoma, a form of skin cancer. The findings, by Mayo Clinic researchers, are published in a new paper in the Journal of Clinical Oncology.
People with MBL fall along a spectrum that spans from a low amount to a high amount of these dysfunctional lymphocytes. Previous research has shown that MBL is a precursor to a type of blood and bone marrow cancer known as chronic lymphocytic leukemia (CLL). People with CLL also have a heightened risk of melanoma.