Cancer is a leading cause of death worldwide, accounting for nearly 10 million deaths in 2020. SOCAN will contribute to the (early) diagnosis and follow up of cancer via a new detection paradigm, i.e. singlet oxygen-based photoelectrochemical detection of cancer biomarkers. Those biomarkers are increasingly discovered and validated, but the detection necessitates rapid, accurate and sensitive devices. To achieve this, the combined use of electrochemical detection with light-triggered sensor technology for the specific and sensitive detection of pre-selected DNA and RNA cancer biomarkers is proposed. The application of this game-changing technology on tissue and liquid biopsy samples will be a major contribution to the early detection of cancer. SOCAN will lead to an affordable and sensitive diagnosis of cancer, reducing the time to result which allows faster and specific treatment, potentially saving lives on the longer term which is in line the EU mission regarding fighting cancer.