MS4A1 and B-cell non-Hodgkin lymphoma: Such an approach has been proven effective in treating relapsed/refractory B-cell lymphomas in which a single dose administration of 131I-tositumomab (Bexxar) or 90Y-ibritumomab (Zevalin), two radiolabeled anti-CD20 chimeric mAbs, afforded high response (47-68%) rates within heavily pretreated populations8–12.