A new generation of molecular tools is becoming available that can digitally record numbers, identities and locations of a broad range of molecular markers for increased diagnostic accuracy. This project will for the first time combine synergistically several groundbreaking technological innovations by the partners, notably padlock and proximity probes with rolling circle amplification for single molecule detection and counting, directed self-assembly of solid phases, and advanced microfluidics and read-out techniques, bringing these from the research lab into integrated instruments useful in routine. This will enable minimally invasive diagnostics, prognostics, and follow-up of treatment of cancers. Blood samples and fine needle aspirates will be subjected to high content, multiplex and multimodal assays of nucleic acids, proteins and interacting complexes thereof in single cells as well as in cell-free bodily fluids. We will use flow cytometry to collect multi-parameter information for large populations of cells, and individual detected molecules will be recorded using a fluorescence activated molecule counter developed by one of the partners. Also, very rare cells and molecules will be targeted through enrichment techniques using novel capturing approaches of unprecedented efficiency. We will apply these diagnostic approaches to characterize biomarkers in solid tumors and in leukemia and lymphoma for minimally invasive diagnostics, monitoring disease progress and selecting optimal therapy, and the assays will be clinically validated in small-scale studies of well-characterized patient samples. This project directly addresses four of the five topics in this call.