The present invention provides a composition comprising at least one agent that interferes with an acute lymphoblastic leukemia (ALL) response signaling pathway in at least one leukemic cell producing an ALL1/AF4 chimeric fusion protein, wherein the agent comprises: an isolated or synthetic ALL1/AF4-specific siRNA which suppresses expression of an ALL1/AF4 chimeric fusion protein； and an isolated or synthetic EphA7-specific siRNA which suppresses expression of EphA7. The present invention also provides a composition comprising at least one agent that interferes with an acute lymphoblastic leukemia (ALL) response signaling pathway in at least one leukemic cell producing an ALL1/AF9 chimeric fusion protein, wherein the agent comprises: 5-iodotubercidin and an ALL1/AF9-specific siRNA consisting of "SEMj" which suppresses expression of an ALL1/AF9 chimeric fusion protein, thereby interfering with an acute lymphoblastic leukemia (ALL) response signaling pathway.
