The same strategy can be applied to detect other less prevalent fusion transcripts (TMPRSS2:ETV1 and TMPRSS2:ETV4) in prostate cancer (2, 5, 6) . In addition, the exon array approach can also be applied to other fusion genes, such as BCR-ABL in CML and clonal Ig/TCR rearrangements in lymphocytic malignancies. While this methodology development was motivated by the clinical need, it is generally applicable to other research requirements that are analogous to the situation for detecting fusion genes in the single cell level when a large excess of normal cells are present. For example, a developmental biologist may use a similar approach to screen mutants that have a desirable gene fusion when direct gene targeting is not feasible.