Induction of apoptosis by BIBF 1000 in patient myeloma cells. Quantification of apoptosis by flow cytometry in CD138⁺-sorted cells from the marrow of a patient with t(4;14)–positive myeloma, [pt 3]). Increased early/late apoptosis by BIBF 1000, dexamethasone, and their combination is depicted in the top row. The bottom row shows partial reversal of apoptosis by IL-6. Percentage quantification of early apoptotic cells (annexin V–positive and propidium iodide [PI]–negative; bottom right quadrants) or late apoptotic cells (annexin V–positive and PI-positive; top right quadrants) as indicated in dot plot panels.