Around 8 to 10 million Americans over age 40 have excess cloned white blood cells (lymphocytes), a condition called monoclonal B-cell lymphocytosis (MBL). Although many with MBL have no symptoms, a Mayo Clinic study shows they may have a higher risk of health issues, including melanoma. MBL is also linked to chronic lymphocytic leukemia (CLL), which raises melanoma risk.
Our study is the first to show that people with MBL have a 92% higher risk of developing melanoma, similar to those with chronic lymphocytic leukemia,” said Dr. Susan Slager from Mayo Clinic. This suggests that MBL, even at low levels, could be an early warning sign for melanoma. Dr. Slager’s team studied over 7,000 people and followed them for four years, finding related diagnoses in those with MBL.
The researchers found that people with MBL also have a higher risk of cancers in the lymphatic system and severe infections, including COVID-19. Dr. Slager explains that MBL isn’t just part of aging; it has health risks like infections and melanoma.
Advances in flow cytometry, a technology that helps examine blood cells, have made it easier to identify MBL, which can lead to CLL.
People with CLL have over 5,000 cloned lymphocytes per microliter of blood, while those with MBL have 1-5. Thanks to better technology, scientists can now detect MBL early.
The study shows that having MBL, no matter the number of cloned lymphocytes, raises the risk of melanoma. Dr. Slager suggests that people with MBL should follow skin cancer prevention guidelines, like using sunscreen and protective clothing.
Dr. Slager’s team will next explore if there is a genetic link between MBL, CLL, and melanoma. They believe a genetic variant that raises the risk of MBL and CLL may also increase melanoma risk. They will also study whether MBL affects melanoma outcomes, such as survival rates or response to treatment.
Journal reference :
- Bryan A. Vallejo, Ahmed Ansari, et al., Risk of Incident Melanoma Among Individuals With Low-Count Monoclonal B-Cell Lymphocytosis. Journal of Clinical Oncology. DOI: 10.1200/JCO.24.00332.
