Rituximab is an anti-CD20 monoclonal antibody (mAb), approved for use in combination with standard chemotherapeutic agents for treatment of patients with CD20-positive B cell lymphomas. Although it provides significant benefits for lymphoma patients, it is not curative, and for several specific forms of lymphoma, rituximab offers little or no benefit. To date, the mechanism(s) underlying the anti-tumour activity of this mAb in vivo are not clear. However, one area of particular interest is in activities that involve clustering of the CD20 molecule on the cell surface. Clustering of CD20 has been shown to elicit changes in cell signalling pathways that promote cell death, while enhancing sensitivity of lymphoma cell lines to cytotoxic agents. By better understanding this mechanism of antibody-induced tumour death it will be possible to determine the clinical basis for insensitivity to rituximab. Jesse Popov’s research is exploring this mechanism of activity by comparing a novel, highly active multivalent form of rituximab that he has developed, to the activity of rituximab. The results of his research will provide for improvements on the novel mAb he has developed and may also provide a possible therapeutic alternative to rituximab. Importantly, this novel agent can be made with any therapeutic antibody, not just rituximab, which means that it has the potential to be used for treating virtually any type of cancer. Such improvements over current therapies translate directly into a higher quality of life for cancer patients.