Our observation that some SVs in HCLc are also found in HCLv-HCLc/IGHV4-34 exomes [13], in CREBBP, KIAA1755 and MUC5B, if verified in larger cohorts of both disease subtypes may reveal shared dysregulated molecular and cellular pathways that are common to origins of HCLc and atypical HCL disease. The gene discussed is MUC5B; the disease is hairy cell leukemia.