Rituximab isthe first FDA licensed and still the most commonly used anti-CD20 monoclonalantibody in B-cell malignancies.5 Since its approval for relapsed/refractory non-Hodgkin’s lymphoma in 1997,rituximab has been endorsed for use in the treatment of numerous other B-cell malignancies.6 This achievement ignited the era of direct monoclonal antibody therapy. The gene discussed is MS4A1; the disease is non-Hodgkin lymphoma.