Improving current cancer detection and treatment follow up through the development of next generation cancer assays.

Each year, an estimated 8.2 million people die of cancer. With appropriate detection methods and treatment, many of these deaths would be avoidable. However, current methods for detection and analysis of treatment response still suffer from major disadvantages. An attractive novel method is the detection of abnormally expressed biological markers manifested during carcinogenesis in so called "liquid biopsies". Liquid biopsy is a technique in which non-solid biological tissues such as urine, stool or peripheral blood, are sampled and analysed for disease diagnosis. The analysis of CtDNA (DNA originating from the tumor and present in the blood) in cancer patients is not new and has been performed in the past. However, until now, a strong focus existed on the detection of tumor specific mutations, which has several limitations, such as limited sensitivity. The use of methylation markers instead of mutation markers has many advantages, such as a potentially much higher sensitivity, and is understudied. We have recently published GSDME as a highly sensitive and specific methylation biomarker for both breast and colorectal cancer. In addition, we have analyzed 12 additional frequent cancer types, and we have strong preliminary data that GSDME is about equally sensitive in each of these 14 tumor types analyzed. These data show that GSDME has strong potential as the first true pan-cancer biomarker. In part A of the project, we will focus on GSDME, and test it as a true biomarker in a clinical setting. Next to detection markers, there is also a need for better follow-up markers. Follow-up of cancer patients is currently performed based on clinical, radiologic and tumor marker evaluation, which has limitations. Better follow-up markers have the potential to detect resistance or disease progression earlier. We aim to expand further on these concepts and conduct a clinical trial where we will evaluate the use of GSDME methylation analysis in liquid biopsies as a tool to guide treatment in metastatic colorectal patients and to explore whether GSDME has potential as a follow up biomarker (WP2). Moreover, GSDME has an interesting physiological function. Recent papers have identified Gasdermins, including GSDME, as a completely new type of regulated cell death executioners (RCD). Recently, it was proven that the N-terminal part of GSDME induces RCD through pore-formation and this is a key antitumor mechanism that is inactivated in several tumor types. In a third work package of part A, we will further investigate these fundamental aspects of the GSDME gene and study its involvement in carcinogenesis. One of the problems with liquid biopsy nucleic acid biomarkers is the limited sensitivity for early detection. Indeed, in early stages of carcinogenesis, many tumor types have low concentrations of CtDNA. Sensitivity can be increased by measuring a multitude of markers simultaneously. However, to date, no efficient techniques exist that allow multi-region methylation analysis in plasma. Therefore, in part B of this project, we will design a novel technique that is able to do this. In a previous unpublished analysis, we have shown that the cancer methylome contains a multitude of differentially methylated makers, that hold the potential to be used as pan-cancer biomarkers, and we have developed a bioinformatics analysis pipeline to detect and rank these according to their discriminating power. Using these data, we will develop a novel multi-region pan-cancer detection assay using our novel technique. We believe that our technology is able to increase sensitivity 100 - 1000 fold while reducing the cost more than a 100 fold compared to the standard technologies that are currently used for CtDNA biomarkers. Finally, we will validate our novel pan-cancer detection assay in the clinical samples that were collected in part A.

Keywords:LIQUID BIOPSY, ONCOLOGY, TUMOR MARKER

Disciplines:Cancer biology, Cancer diagnosis