Application of in situ DNA hybridization technology to diagnostic surgical pathology

Using cloned genes obtained through the latest recombinant DNA technology as probes, and relying on the property that these DNAs bind only to their own complementary sequences through hydrogen bonds, it is now possible to detect many genes of pathologic interest in clinical specimens. In molecular biology laboratories, such hybridization reactions are usually performed on target DNA which has been bound and immobilized on filter membranes, using highly radioactive DNA probes and subsequent auto-radiography for detection. In this review the authors focus on the advent of two recent discoveries which have now allowed this technology to leave the rarified domain of the research laboratory and become applicable to routine use in diagnostic pathology: the ability to label DNA probes by nonradioactive methods and the finding that endogeneous nucleic acid sequences in tissue sections and cytologic smears can be used as targets for these probes directly on the microscope slide by in situ hybridization