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. 2018 Jan;55(1):668-681.
doi: 10.1007/s12035-016-0345-x. Epub 2016 Dec 19.

Evaluating the Feasibility of DNA Methylation Analyses Using Long-Term Archived Brain Formalin-Fixed Paraffin-Embedded Samples

Stine T Bak  1 , Nicklas H Staunstrup  1   2   3   4 , Anna Starnawska  1   3   4 , Tina F Daugaard  1 , Jens R Nyengaard  5   6 , Mette Nyegaard  1   3 , Anders Børglum  1   3   4   7 , Ole Mors  3   4   7 , Karl-Anton Dorph-Petersen  2   6   8 , Anders L Nielsen  9   10
Affiliations

Evaluating the Feasibility of DNA Methylation Analyses Using Long-Term Archived Brain Formalin-Fixed Paraffin-Embedded Samples

Stine T Bak et al. Mol Neurobiol. 2018 Jan.

Abstract

We here characterize the usability of archival formalin-fixed paraffin-embedded (FFPE) brain tissue as a resource for genetic and DNA methylation analyses with potential relevance for brain-manifested diseases. We analyzed FFPE samples from The Brain Collection, Aarhus University Hospital Risskov, Denmark (AUBC), constituting 9479 formalin-fixated brains making it one of the largest collections worldwide. DNA extracted from brain FFPE tissue blocks was interrogated for quality and usability in genetic and DNA methylation analyses by different molecular techniques. Overall, we found that DNA quality was inversely correlated with storage time and DNA quality was insufficient for Illumina methylation arrays; data from methylated DNA immunoprecipitation, clonal bisulfite sequencing, and pyrosequencing of BDNF and ST6GALNAC1 suggested that the original methylation pattern is indeed preserved. Proof-of-principle experiments predicting sex based on the methylation status of the X-inactivated SLC9A7 gene, or genotype differences of the Y and X chromosomes, showed consistency between predicted and actual sex for a subset of FFPE samples. In conclusion, even though DNA from FFPE samples is of low quality and technically challenging, it is likely that a subset of samples can provide reliable data given that the methodology used is designed for small DNA fragments. We propose that simple PCR-based quality control experiments at the genetic and DNA methylation level, carried out at the beginning of any given project, can be used to enrich for the best-performing FFPE samples. The apparent preservation of genetic and DNA methylation patterns in archival FFPE samples may bring along new perspectives for the identification of genetic and epigenetic changes associated with brain-manifested diseases.

Keywords: Archival FFPE samples; Biobanks; Epigenetics; Post mortem examination; Tissue procurement; Tissue quality.

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References

    1. Nat Methods. 2010 Feb;7(2):133-6 - PubMed
    1. Nucleic Acids Res. 2010 Aug;38(14):e151 - PubMed
    1. PLoS One. 2010 Dec 23;5(12):e15367 - PubMed
    1. Nucleic Acids Res. 1996 Dec 15;24(24):5026-33 - PubMed
    1. Pathol Res Pract. 1993 Feb;189(1):66-72 - PubMed

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