In this study, we assessed a total of 131 patients with different B-cell CLDs, including B-CLL, atypical B-CLL, MCL, and CD5-/CD10-lymphoma, for a panel of B-cell-specific markers viz CD5, CD20, CD22, CD23, and FMC-7. The gene discussed is MS4A1; the disease is B-cell chronic lymphocytic leukemia.