CASP8 and plasma cell myeloma: Nonetheless, active caspase-8-mediated apoptosis of myeloma cells might be an edge effect of lenalidomide, because cleaved caspase-8 was not detected after a lenalidomide challenge in myeloma cells (5, 44, 45), which indicated that lenalidomide might promote the activities of caspase-8 to low levels that are non-lethal for myeloma cells.