FISHing — Current Status and Future Prospects for Improved Management of Leukemia

Abstract

It is now mandatory to perform cytogenetics (CG) study in all new cases of leukemia owing to its usefulness in disease diagnosis, classification and prognostication. The technique of fluorescence in-situ hybridization (FISH), applicable to both interphase and metaphase cells on a variety of samples has proved to be useful in supplementing convention CG, especially in the detection of clinically significant changes when CG is unsuccessful or when genetic abnormalities are cryptic. With improvements in the test sensitivity, FISH can be applied in monitoring molecular response to treatment and detection of residual disease, especially in the setting of monitoring for BCR-ABL in chronic myeloid leukemia patients following imatinib therapy. Newer molecular CG tests such as multicolor karyotyping and comparative genomic hybridization have a clinical potential as they enable resolution of complex karyotypic aberrations and global scanning of genomic imbalances, respectively. In the horizon, important information gained from gene expression profile studies will be useful for the design of tests, molecular based or otherwise, that are suited for routine diagnostic service. However, CG and molecular data must also be integrated with clinical and pathological findings before a definitive diagnosis is made.