What? Early detection of cancer is a key determinant for patient survival. This project seeks to develop a blood based screening test capable of detecting a broad range of cancer types, and additionally point to the specific organ in which the tumor resides. The test will analyze two different components in blood samples: tumor-derived DNA fragments leaking from the tumor site and intact cancer cells that have invaded and entered the blood circulation. The analyses will focus on DNA methylation patterns, which is an epigenetic event occurring at certain residues in the DNA sequence. Aberrant methylation patterns are known to be present in tumor-derived DNA at early stages of disease, and occurs in a tissue-specific manner, making them an attractive alternative for cancer screening. Why? The results from this project will have a high impact on future screening strategies. It will provide a roadmap of methylations biomarkers that enables the detection of a broad range of cancer types suitable for high throughput screening in a clinical setting. Furthermore, detection of circulating tumor cells is an unequivocal diagnosis validating the screening results. This is the first study combining circulating tumor DNA and CTC analysis with the aim of improving the sensitivity of early cancer detection and accurately determine the tumor tissue of origin. How? In the first phase of the project I will identify and test a panel of methylation biomarkers. The assay will consist of small DNA probes that are designed to bind and capture and cancer-specific DNA stretches. Using a technique, called bisulfite sequencing, it will be possible to identify the cancer-related DNA methylation patterns. Initially, this will be tested on plasma samples from cancer patients with known type of disease. In the second part, circulating tumor cells will be extracted from blood samples and analyzed for their DNA methylation patterns at single cell level. The advantage of this is that these cells carry information from the entire genome. Finally, we will test and validate the screening test in blood samples from a broad range of cancer patients.