Sufficient DNA target integrity in long-term biobanked screening samples enable future biomarker studies

Objective To evaluate the suitability of regular cervical screening samples collected during 2007–2013 and stored long-term at − 80 °C, following different pre-storage processing methods, for DNA methylation biomarker analyses. Results Valid DNA methylation results, indicating sufficient sample quality, were defined by positive control gene signals (ACHE and IDS-M) in the GynTect assay. Samples stored in ThinPrep fixative showed optimal performance with 100% valid results, compared to 57% for STM samples and 27% for nucleic acid extracts. Neither long-term storage nor a 25-fold reduction in sample input significantly affected assay performance. These findings suggest that long-term biobanked screening samples can be suitable for DNA methylation–based biomarker analyses, and potentially other molecular biomarker assays.