FISH in cancer diagnosis and prognostication: from cause to course of disease.

The last 20 years have witnessed an astounding evolution of cytogenetic approaches to cancer diagnosis and prognostication. Molecular techniques and, in particular, nonisotopically-labeled nucleic acid probes and fluorescence in situ hybridization (FISH)-based techniques have replaced the costly and potentially dangerous radioactive techniques used in research and the clinical detection of genetic alterations in tumor cells. Fluorescent DNA probes also enabled the screening for very subtle chromosomal changes.