Formalin-Fixation followed by paraffin-embedment (FFPE) is one of the most widely practiced methods for preservation and archiving of clinical tissue samples. It is estimated that worldwide, over a billion FFPE tissue samples are being stored in numerous hospitals, tissue banks, and research laboratories. These archived samples could potentially provide a wealth of information in retrospective molecular studies (from: PMID:20147068 ). The retrospective molecular studies based on well-described clinical material are essential for validation of the clinical utility of molecular biomarkers including methylation-based biomarkers.
The Methylation-Sensitive High-Resolution melting technology (MS-HRM) was shown to allow for stable methylation assessment in 30 years old archival FFPE material, see: PMID:20025721. Moreover, the level of degradation of DNA in FFPE samples was shown not to affect the performance of methylation detection by Methylation-Sensitive High-Resolution Melting (MS-HRM), see: PMID:26551081.