Differential effects of chemotherapy against overt leukemia are observed in vivo. (A) Survival of mice treated with chemotherapy 25 days after engraftment with MA9-NRas AML cells. (B) Survival of mice treated with chemotherapy 35 days after engraftment with MA9-ITD AML cells. (C) The BM grafts of mice in (B) were determined before therapy and show that treatment delays death in mice with roughly equivalent grafts. (D) Individual data points from (C) plotted to show correlation of survival with measured AML graft in mice treated with PBS and DA. (E) Flow cytometry plots demonstrating a reduction of AML burden in a mouse with a significant human AML patient sample graft following combined DA chemotherapy. (F) Summary of additional experiments performed with other AML patient samples and cell lines showing variable response in vivo. *P < .05 by the log-rank test. ARAC, Ara-C (cytarabine); DOXO, doxorubicin.