MS4A1 and mantle cell lymphoma: Immunotherapy directed at CD20 is extensively employed for treating mature B cell-derived malignancies, such as chronic lymphocytic leukemia (CLL) and various B cell-derived non-Hodgkin lymphomas (B-NHL), including follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL).