The art and applications of fluorescence in situ hybridization in endocrine pathology

Fluorescence in situ hybridization (FISH) or molecular cytogenetics is curr ently recognized as a reliable, sensitive, and reproducible technique for i dentifying the copy number and structure of chromosomes. FISH combines mole cular genetics with classic cytogenetics and allows simultaneous morphologi c evaluation on a single slide. Centromeric DNA probes are used to detect s pecific chromosomes and telomeric probes to demonstrate all chromosomes, Se quence-specific probes can localize in situ a single gene copy on a specifi c chromosome locus, FISH allows cytogenetic investigation of metaphase spre ads and interphase nuclei. Several protocols have been proposed to analyze preparations from fresh samples or archival material. Comparative genomic h ybridization (CGH) is a novel cytogenetic technique, which combines FISH wi th automatic digital image analysis. Comparative analysis of the hybridizat ion products of tumor DNA and reference DNA with normal metaphase chromosom es, each labeled with color different fluorochrome, can retrieve chromosoma l imbalances of the entire genome in a single experiment. FISH and CGH are powerful morphologic tools in understanding physiologic mechanisms and in r esolving problems of the pathogenesis of several diseases, These techniques shed light on the cytogenetic background in many endocrinological disorder s, providing a better understanding of the activities and alterations of en docrine cell function.