CD44 and PS exposure on the surface of leukemic cells contributes to the in situ deposition of fibrin. (A) Flow cytometry was used to quantify apoptotic cells stained with lactadherin after treatment with chemotherapy drugs. (B) The percentage of apoptotic leukemic cells. (C) A total of 1 × 106 target APL cells were incubated with coagulation reaction substrates, and the production of thrombin, intrinsic FXa, and extrinsic FXa was measured by using a microplate reader. (D) Leukemia cells with various treatments were incubated with fibrinogen and coagulation reaction substrates in the presence of lactadherin or thrombin. Fibrin absorption was evaluated by using a microplate reader. (E) Leukemic cells treated as described above were stained with lactadherin (green), fibrinogen (red), and 4′,6-diamidino-2-phenylindole (DAPI; blue). Scale bars, 20 µm. Each image was from 5 experiments. **P < .01 in panel B. *P < .05 vs the data in the DNR group in panel C. *P < .05 vs the control, #P < .05 vs the DNR group in panel D. Each value was from at least 3 experiments and is shown as the mean ± standard deviation. Ctrl, control; ns, not significant; PI, propidium iodide.