A splice variant of bcr-abl mRNA that produces BCR-ABL protein with a truncated C-terminus and its role in resistance to treatment with kinase inhibitors is disclosed. Vectors for expressing the truncated gene product are provided as well as recombinant cells that express the truncated gene product from a cDNA construct. Also provided are methods compositions and kits for detecting the BCR-ABL splice variant. Additionally, methods for screening BCR-ABL kinase domain inhibitors which rely on the recombinant cells and methods of predicting likelihood for resistance of a CML patient with a BCR/ABL translocation respond to treatment with one or more BCR-ABL kinase inhibitors are also disclosed.