Conditional knockout of survivin abrogates leukemia in vitro. (A) Schematic of oncogenic transformation of IL-7–primed BM harvested from survivin floxed (survivin^fl/fl) mice transformed with BCR-ABL p210 retrovirus. Subsequent to leukemic outgrowth after cytokine withdrawal, cultured cells were transduced with either GFP control or the Cre-GFP vector to inducibly delete survivin. (B) Conditional knockout of survivin. The presence of floxed and deleted survivin alleles in transduced cells was confirmed by PCR of genomic DNA. (C) Cre-GFP- and GFP control–transduced BCR-ABL p210 murine leukemia cultured cells were monitored for GFP expression by flow cytometry. Statistical analyses were performed at 120 hours. P < .0006.