Fluorescence In Situ Hybridization (FISH): Definitions

The page below is a sample from the LabCE course HER2 Testing in Breast Cancer. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about HER2 Testing in Breast Cancer (online CE course)
Fluorescence In Situ Hybridization (FISH): Definitions

A hybrid is the combination of two or more different things, aimed at achieving a particular objective or goal. Unpaired strands of DNA can hybridize in a specific way. This is used to detect specific nucleic acid sequences in tissue, cytologic, or chromosome preparations. In situ means that the gene or protein can be examined in place exactly where it occurs.
Hybridization is useful for:
  • Confirmation of the presence or absence of a gene
  • Amplification of a gene
  • Rearrangement of chromosomes
  • Aneuploidy