The invention relates to human nucleotide sequences which occur as a result of the t(1;22)(p13;q13) chromosomal translocation event which is known to occur almost invariable in young children with acute megakaryoblastic leukemia. The translocation results in the formation of fusion genes which encode fusion proteins. The invention provides the nucleotide sequences of transcripts of the fusion genes and the amino acid sequences of the fusion proteins encoded thereby. Also provided are methods for detecting the t(1, 22) translocation, for identifying agents capable of binding to the fusion protein and for identifying agents useful for treating patients with acute megakaryoblastic leukemia.