Colorectal cancer and lung cancer cause millions of death each year. Currently there is no suitable non-invasive method for the early detection of these types of cancer. The tumour suppressor gene BARD1 (BRCA1-associated RING domain protein) is aberrantly expressed in several types of cancer and could be a diagnostic target for early cancer diagnosis in blood samples. The overall objective of the project is to develop blood tests for the early detection of colorectal and lung cancer based on cancer-specific BARD1 isoforms. The outlined tests will analyse BARD1 isoforms at two levels: the expression of isoform-specific RNA in circulating tumour cells (CTC) and the presence of isoform-specific autoantibodies in serum. To reach these objectives, several technological challenges have to be overcome. The BARDiag consortium includes 3 SMEs and 4 research centres, who have excellent expertise, specific knowledge, the required lab infrastructure and necessary clinical materials that will enable to conduct this project. Within the frame of the project, innovative methods for the isolation of CTCs in colorectal and lung cancer patients will be developed, the specific signatures of the BARD1 isoforms at both mRNA and autoimmune levels will be defined, and assays for the detection of these isoforms will be established, validated with clinical samples and tested for their marketability. The results of the proposed project will have extensive impacts. Not only more scientific knowledge on the expression of BARD1 isoforms in colorectal and lung cancer will be obtained and therefore the understanding for cancer will be improved, but also non-invasive methods for the early detection of colorectal and lung cancer will be made broadly available in form of commercial test kits. The SMEs will extend their expertise and knowledge and therefore strengthen their economic power, which will contribute to increase European competitiveness.