Circulating biomarkers för detection and surveillance of cancer

In precision medicine in oncology, the patient's treatment and follow-up is personalized for example with genetic characterization of the tumor to predict whether the patient will respond to the treatment or not. The genetic analysis is done on the tumor tissue biopsy but that involves an invasive sampling and on top of that, the tumor can be heterogeneous, which means that a biopsy can miss the relevant cells for the analysis. Using circulating biomarkers, liquid biopsy, instead avoids these problems. Circulating biomarkers can also be used to monitor the effect of a treatment and detect disease relapse early. In recent years, several new types of blood biomarkers have been discovered, such as circulating cell-free DNA. When cells are metabolised, their contents, including short fragments of DNA, leak into the bloodstream. The release occurs during necrosis, apoptosis or active secretion. The portion of circulating cell-free DNA that originates from tumor cells is called circulating tumor DNA. Other types of molecules, such as microRNA, proteins, metabolites and extracellular vesicles are also free in the circulation and could potentially be used as circulating biomarkers.

Our research focuses on finding circulating biomarkers that can be used for diagnosis, treatment selection and to monitor the patient during treatment and we have two clinical studies ongoing in oropharyngeal cancer, cancer of unknown primary and patients with nonspecific symptoms of cancer.

• In the Allvos study, we include patients who are investigated in the standardized care pathway: "Severe non-specific symptoms that may be due to cancer" and patients with cancer of unknown primary. In this project, we want to develop a test to detect cancer in a blood sample and to determine the tissue of origin of the tumor by combining different types of circulating biomarkers.
• In the Circos study (clinicaltrials.gov NCT05904327), we include patients with cancer in the oropharynx and monitor them after treatment to detect recurrent disease. Circos is a multicenter study where blood samples are collected before treatment, after treatment and in connection with the patient's regular return visit. We are primarily investigating circulating tumor DNA from human papillomavirus as a biomarker for early detection of recurrence but have collected patient samples to also analyze other circulating biomarkers.