Does Low-Count Monoclonal B-Cell Lymphocytosis Increase the Risk of Melanoma?

By: Chris Schimpf, MSW
Posted: Monday, October 14, 2024

New research published in the Journal of Clinical Oncology suggests that monoclonal B-cell lymphocytosis (MBL)—an overabundance of cloned lymphocytes understood to be a precursor of chronic lymphocytic leukemia (CLL)—may also indicate an elevated risk for melanoma, even at low levels. Susan L. Slager, PhD, of the Mayo Clinic, Rochester, Minnesota, and colleagues found in their large cohort study that individuals with MBL classified as low count demonstrated a 92% elevated risk of incident melanoma. Highlighting the approximately twofold increase also observed in patients with CLL, the researchers suggested the increased risk of melanoma among individuals with CLL may begin with the onset of MBL.

“Previously, scientists would equate MBL as just a part of the aging process,” said Dr. Slager in a Mayo Clinic press release. “What we’re seeing, though, is there are clinical consequences to having MBL—contracting serious infections and melanoma are some of them.”

Using the Mayo Clinic Biobank, the investigators identified 7,334 participants (aged 40 or older) with no previous hematologic malignancies and biospecimens available for screening. Eight-color flow cytometry was then used to identify a total of 1,151 participants with CD5-positive MBL, of whom 1,098 had low-count MBL.

After a median follow-up of 3.2 years (range = 0–13.5 years), 131 participants developed melanoma, of whom 36 had MBL. After adjusting for age, sex, and history of melanoma, the researchers observed a 1.86-fold (95% confidence interval [CI] = 1.25–2.78) increased risk of melanoma among those with MBL, which persisted when restricted to those without a history of melanoma (hazard ratio [HR] = 2.05; 95% CI = 1.30–3.23). In addition, individuals with low-count MBL had a 1.92-fold (95% CI = 1.29–2.87) increased risk of melanoma overall and a 2.74-fold (95% CI = 1.50–5.03) increased risk of melanoma in situ compared with those without MBL.

Disclosure: Dr. Slager reported no conflicts of interest. For full disclosures of the other study authors, visit ascopubs.org.

Journal of Clinical Oncology