Megakaryopoiesis and TSP-1 expression are increased in the bone marrow of tumor-bearing wild-type mice. (A) Western blot for TSP-1 expression in megakaryocytes isolated from the bone marrow of Lewis lung tumor-bearing mice. β-Actin was probed as a loading control. (B) Tsp-1^−/− mRNA levels in bone marrow megakaryocytes were quantified by quantitative polymerase chain reaction and compared with the housekeeping gene GAPDH before tumor growth (0), and when tumors reached 100 mm³ and 500 mm³ in volume. (C) Immunofluorescence analysis of bone marrow cytospins with anti-GPIBα (red) and Hoechst (blue) to detect megakaryocytes. Bar represents 50 μm. Right: Quantification of GPIBα⁺ cells in the bone marrow of non–tumor-bearing (0) or tumor-bearing mice (500 mm³). (D) Femurs from control and tumor-bearing wild-type and Tsp-1^−/− mice were stained with hematoxylin and eosin. Arrows indicate megakaryocytes. Bar represents 50 μm.