Cervical cytology biobanking: quality of DNA from archival cervical Pap-smears

Abstract

Cervical cytology biobanking is a feasible concept in cervical pathology and could be an indispensable tool for fundamental and applied molecular biological research. Polymerase chain reaction (PCR) is a powerful molecular technique that can be performed on a variety of cervical sample types including Papanicolaou (Pap)-stained cervical smears. However, since the quality of DNA from such specimens is inferior to that from fresh tissue, proper processing methods seem required. This study evaluates 3 commercial isolation methods and 1 digestion procedure for their ability to obtain DNA suitable for PCR from fixed and stained Pap-smears. Amplification of â-globin was performed to verify the presence and integrity of target DNA. The influence of PCR inhibitors and extent of DNA fragmentation were analysed. All commercial DNA isolation techniques provided DNA suitable for PCR amplification. Conversely, crude proteinase K digestion did not consistently yield amplifiable digests, as these are contaminated with PCR-inhibiting factors and debris. Furthermore, our study indicates that DNA isolated from ten-year-old archival smears can yield amplicons up to 400bp, while proteinase K digestion limits the amplicon size to 300bp.