Monoclonal B-cell Lymphocytosis Carries Increased Melanoma, Melanoma In Situ Risk

By Andrew Moreno - Last Updated: September 25, 2024

A recent biospecimens study evaluated whether patients who have monoclonal B-cell lymphocytosis (MBL) have an elevated risk for melanoma, as observed in chronic lymphocytic leukemia. The study classified MBL cases by clonal B-cell percentage and found low-count (LC) MBL to carry an increased risk for both melanoma and melanoma in situ. The results were published in the Journal of Clinical Oncology.

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The study investigators searched the Mayo Clinic Biobank and compiled a total cohort of 7,334 patients, all aged at least 40 years with biospecimens available for MBL screening. Eight-color flow cytometry found CD5-positive MBL in 1,151 patients, 1,098 of whom had LC-MBL.

Of the cohort with a median follow-up of 3.2 years, melanoma developed in 131 patients and 36 screened positive for MBL. The investigators estimated a five-year cumulative incidence of melanoma of 3.4% among patients with MBL and 2.0% among those without MBL.

The investigators applied Cox regression models and, after adjusting for age, sex, and previous melanoma history, determined the risk for melanoma increased by 1.86 times in patients with MBL. An increased risk was calculated even in patients who did not have a history of melanoma (Hazard ratio: 2.05).

Compared to patients without MBL, patients with LC-MBL were had a 1.92 times greater risk of melanoma onset overall and a 2.74 times greater risk of melanoma in situ.

Reference

Vallejo BA, Ansari A, Parikh SA, et al. Risk of incident melanoma among individuals with low-count monoclonal B-cell lymphocytosis. J Clin Oncol. 2024. doi:10.1200/JCO.24.00332

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