Three distinct subtypes based on immunotypic features have been identified: CLL-like MBL (CD19+, CD20dim, CD5+, CD20+, surface Igdim, FMC7-), atypical CLL-like MBL (CD19+, CD20bright, CD5+, CD23-, FMC7+/-), and CD5- MBL which resembles marginal zone lymphoma [35]. This evidence concerns the gene MS4A1 and B-cell chronic lymphocytic leukemia.