TNFSF13B and plasma cell myeloma: These observations led investigators to study elements of the BAFF–APRIL system as potential therapeutics in hematologic malignancies: Anti-APRIL antibodies have been tested in vitro and in experimental animals in B cell lymphomas (91, 92) and multiple myeloma cells and xenografts (93–95); anti-BAFFR antibodies have been studied in multiple myeloma (96–98) with moderate results, alone or in combination with proteasome inhibitors.