Immunohistology of bone marrow biopsies of patient no. 13. Immunohistochemistry of bone marrow biopsies of patient 13 collected before therapy and on day 28 of first cycle. The bone marrow sections were stained for total and phosphorylated forms of VEGFR-2, c-kit, and the phosphorylated forms of the signal transduction intermediates STAT5 and Akt (magnification × 400).