Epigenomic Profiling of Circulating Cell-Free DNA (cfDNA) to Characterize the Dynamic Evolution of Molecular Subtypes in Extensive-Stage Small Cell Lung Cancer During First-Line Chemoimmunotherapy

The EPICIRC SCLC project aims to improve our understanding and treatment of extensive-stage small cell lung cancer (ES SCLC), the most aggressive form of lung cancer that accounts for 15% of all cases. Despite current treatments, which combine chemotherapy with immunotherapy, the outlook for patients remains poor, with an average survival of just 12 months. Recent research has shown that this cancer can be classified into four subtypes, which respond differently to anti-cancer treatments. However, these subtypes may change over time, particularly during chemotherapy, which could explain why many patients eventually become resistant to treatment. Understanding how these subtypes evolve could pave the way for better treatment strategies, but it has been difficult to study these changes because new tumor samples are rarely collected after a patient is diagnosed. The EPICIRC SCLC project tackles this challenge by using liquid biopsies, a minimally invasive technique that analyzes circulating free DNA (cfDNA) found in patients blood. This approach allows to monitor changes in the tumor's molecular profile over time without needing additional tissue samples. By collecting and analyzing blood samples from patients at three key points-before treatment, after four cycles of chemo-immunotherapy, and at disease progression-the project aims to track the evolution of the tumor's molecular subtypes and identify patterns associated with treatment resistance. Using advanced epigenomic technologies, we will study how genes are regulated and how their activity changes during treatment. This will provide a detailed map of the tumor's molecular evolution and could uncover new targets for future therapies. In the long term, these findings would lead to more personalized treatment strategies, helping clinicians select therapies based on the specific molecular profile of each patient's cancer at different stages of their treatment.