DNA methylation is an epigenetic mechanism modulating the function and expression of genes. DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA. Changes in DNA methylation are associated with numerous diseases and abnormal DNA methylation has been implicated as one of the mechanisms driving tumor onset, development, progression and recurrence. Identification of tumor-associated methylation patterns is of great diagnostic potential, especially for early detection of disease. In Part 2 of this two-part blog series, the article continues to review the methylated DNA biomarkers in plasma webinar. As a reminder, Part 1 covered the main themes discussed by our invited webinar speakers - click here to read that article. To conclude the recent webinar hosted by LGC Clinical Diagnostics and GenomeWeb, Dr. Yves Konigshofer talked about levels of evidence required for clinical diagnostics, from analytical validity through clinical validity and clinical utility. Reference materials can help prove analytical validity and assess the impact of pre-analytical factors. Methylation reference materials that he is currently developing at LGC CDx address the analytical validity of 5’methylcytosine measurements in cfDNA.