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Extraction and amplification of DNA from archival haematoxylin and eosin sections and cervical cytology Papanicolaou smears.

The clinical application of molecular biological techniques has been greatly facilitated by the use of archival pathological material. Extraction of DNA from paraffin-embedded blocks and fresh cervical cytology specimens has been described (1,2), however, these are not always available. We describe the use of archival haematoxylin and eosin (H&E) stained sections andPapanicalaou (Pap) stained cervical smears for polymerase chain reaction (PCR) amplification. The archival slide, a parallel newly prepared stained slide and an unstained 5 micron section from each of five stored paraffin-embedded blocks five, ten and twenty years old were used, as well as two 10 year old Pap stained, mounted cervical smear preparations. Coverslips were removed by soaking in warm xylene for two days, and DNA extracted as previously described (3). This was assayed quantitatively by fluorimetry, and qualitatively by 0.7% agarose gel electrophoresis (Fig. A). A standard PCR protocol was used to amplify a 120 bp fragment of the K-ras gene (4) from the extracted DNA. PCR products were analysed by 2% agarose gel electrophoresis (Fig. B).