Since most cervical cancers are HPV-associated, primary cervical scereening is changing to HPV test in many European countries. HPV testing techniques are mainly based on direct DNA hybridization or nucleic acid amplification. HPV DNA testing may be performed directly from residual liquid-based cytology (LBC) specimens. In some cases, particularly in retrospective studies or for quality control purposes, previously archived samples may be used. In these cases, DNA degradation may become a potential issue. The aim of this study was to evaluate the reproducibility of HPV typing on archived LBC-specimens with the Real Time PCR (RT-PCR)- based Xpert® HPV assay (Cepheid, Sunnyvale, USA).
A total of 150 LBC samples (ThinPrep, Hologic, Inc. Marlborough, MA-USA) with a previous positive HPV test with Hybrid Capture II (HCII, Qiagene GmbH, Hilden-Germany), were included in the study and divided in 3 groups. Group 1 included 50 samples that were typed with the xpert assay immediately after the positive HCII test. Group 2 and Group 3 included 50 cases each with a previous positive HCII test which had been carried out 12 and 36 months before, respectively.
The observed agreement between Xpert® HPV assay and the previous HCII test was 96% for the first Group, 90% for the second Group and 94% for the third Group. The observed agreement didn’t differ significantly among the tree groups (p = 0.606).
These results show that HPV-typing by the RT-PCR based Xpert assay is reproducible even in long-term stored archival LBC-specimens. This may be relevant particularly for retrospective studies or for quality control purposes.