Molecular Cytogenetics: An Indispensable Tool for Cancer Diagnosis

Cytogenetic aberrations may escape detection or recognition in traditional karyotyping. The past decade has seen anexplosion of methodological advances in molecular cytogenetics technology. These cytogenetics techniques add color to theblack and white world of conventional banding. Fluorescencein-situ hybridization (FISH) study has emerged as an indispensable tool for both basic and clinical research, as well asdiagnostics, in leukemia and cancers. FISH can be used toident i fy chromosoma l abnorma l i t i e s through f luor e s c entlabeled DNA probes that target specific DNA sequences.Subsequently, FISH-based tests such as multicolor karyotyping, comparative genomic hybridization (CGH) and arrayCGH have been used in emerging clinical applications as theyenable resolution of complex karyotypic aberrations and wholeglobal scanning of genomic imbalances. More recently, crossspecies array CGH analysis has also been employed in cancer gene identification. The clinical impact of FISH is pivotal, especially in the diagnosis, prognosis and treatment decisionsfor hematological diseases, all of which facilitate the practice of personalized medicine.This review summarizes the methodology and current utilization of these FISH techniquesin unraveling chromosomal changes and highlights how the field is moving away from conventional methods towards molecular cytogenetics approaches. In addition, the potential ofthe more recently developed FISH tests in contributing information to genetic abnormalitiesis illustrated.