IN-SITU POLYMERASE CHAIN-REACTION (IN-SIT U PCR) - A NEW MOLECULAR TECHNIQUE FOR PATHOLOGISTS

In situ polymerase chain reaction is a recent technique which combines the sensitivity of PCR reaction to intracellular localizatin of genom ic sequences with the same specificity as in situ hybridization. This reaction is based on the in situ annealing and polymerization of oligo nucleotides complementary to nucleotides located at each side of the t arget DNA sequence to amplify. We describe the Hot Start PCR (DNA) and the Hot Start PCR after reverse transcription step (RNA). It allows t o amplify some nucleic sequences to a high level, becoming easier to d etect. The visualization can be realized by direct in situ PCR, the pr oduct obtained being directly identifiable by incorporation of labeled nucleotides or primers, or preferentially by indirect in situ PCR. In this case, the amplification is followed by in situ hybridization wit h labeled probes. This last procedure is more specific. Numerous contr ols are essential at each step of the technique for validating results .