In Situ PCR: An Overview

In contrast to the immediate and enormous impact that solution-phase polymerase chain reaction (PCR) had in molecular biology, morphologists have regarded the development of in situ PCR with cautious expectancy (1 ,2 ). The notion of employing a PCR-based amplification step to increase the sensitivity of in situ hybridization (ISH) apparently came to several laboratories independently in the late 1980s (3 –6 ). The result has been a relatively small number of publications detailing at once some successes, certain problems and limitations of the technique, and a variety of different technical approaches to combining the technologies of ISH and PCR. As we approach the end of the 1990s, it seems likely that the relative importance of the variables identified will be agreed on and that some consensus concerning optimization of the multiple steps involved will emerge, paving the way for standardized protocols that may serve to establish in situ PCR in diagnostic laboratories.