This presentation explored the development and clinical application of methylation-based biomarkers, with a focus on digital PCR (dPCR) for the real-time monitoring of cancer patients. Valerie Taly, Research Director & Group Leader, University of Paris Descartes introduced her background in academic research and her involvement in spin-off companies, notably METHYSDX and Emulseo, which translate laboratory innovations into clinical tools.
The talk began by highlighting the urgent need for sensitive, quantitative methods to track cancer progression, given the disease’s genetic complexity and the low abundance of tumour-derived DNA in blood. Circulating tumour DNA (ctDNA) is emphasised as a minimally invasive, dynamic biomarker that reflects tumour heterogeneity and burden, enabling real-time patient monitoring.
Taly recounted the evolution from traditional qPCR and NGS methods to digital PCR, which offers superior sensitivity and quantification. Early work involved adapting methylation markers (such as WIF1 and NPY) for dPCR, demonstrating high sensitivity and specificity in detecting colorectal cancer across all stages. The approach was expanded to other cancers, including gastric, lung, pancreatic, and endometrial cancers, with tailored methylation signatures for each.
Clinical studies were presented showing that both the baseline concentration and dynamic changes in ctDNA during treatment are strong prognostic indicators for progression-free and overall survival. Notably, rapid decreases in ctDNA after therapy initiation predict better outcomes, especially in patients receiving immunotherapy. The technology also enables early detection of relapse and identification of high-risk patients, even in cancers typically considered low risk, such as early-stage endometrial cancer.
The presentation concludes that liquid biopsy using methylation-based dPCR can efficiently replace invasive tissue biopsies for many patients, supporting treatment decisions and improving patient stratification. The importance of rigorous pre-analytical standards and ongoing collaborative efforts to establish clinical guidelines is also stressed.
