MS4A1 and lymphoma: Strategies to overcome rituximab resistance associated with altered CD20 structure/expression levels include generation of novel anti-CD20 mAbs with higher binding affinity and/or re-engineered Fc regions facilitating more efficient CMC or ADCC, re-expression of CD20 antigen by changing its epigenetic regulation through the use of cytokines such as GM-CSF, targeting of multiple antigens through the use of multivalent antibodies, developing a bivalent antibody with enhanced CMC and direct killing, and developing novel antibodies that target other lymphoma-associated antigens.