5 mL Blood Test Predicts Effectiveness of Cancer Immunotherapy

Scientists have developed a new diagnostic method that can predict the effectiveness of cancer immunotherapy using just 5 milliliters of blood. The key lies not only in "knowing the enemy" but also in "knowing oneself." Cancer is a result of abnormal interactions between cancer cells and the immune system. Treatment methods include immunotherapies such as PD-1 and PD-L1 antibodies and CAR-T cell therapy, as well as non-immunological treatments like chemotherapy, radiation therapy, and surgical interventions. Although immunotherapy has emerged as a significant approach in cancer treatment, it is effective only for a fraction of patients. Current prediction methods are limited, making the development of new biomarkers that can accurately predict immunotherapy outcomes crucial. The new technique, called ETAST (Enhanced Tumor Antigen-Specific T cell), serves as the "main force" in identifying and quantifying the specific immune responses to cancer antigens. It measures the quantity and activity of ETAST, which can most accurately reflect a patient's tumor-specific immune response. The research team has innovatively developed an ETAST detection method based on the capture of cancer-specific antigen-presenting cells using magnetic nanoparticles. By activating the ETAST from the surrounding blood and combining it with flow cytometry, they can comprehensively and precisely measure its content. Many cancer immunotherapy treatments work by stimulating pre-existing effective ETAST or triggering the production of new ones in the patient's body. Therefore, the quantity of ETAST can serve as an indicator of the effectiveness of immunotherapy. Each type of T cell can recognize only one specific antigen, while a cancer patient may have between 100,000 to 1 million different types of cancer antigens. This could potentially stimulate the production of hundreds of millions of different ETASTs. To achieve comprehensive and precise detection of various ETASTs, each type must be distinguished from other T cells. However, separating individual ETASTs from the vast array of T cells is a significant challenge. The new technique addresses this by using magnetic nanoparticles to capture and isolate the antigen-presenting cells, followed by activation and measurement using flow cytometry. This method promises to revolutionize our ability to predict the success of immunotherapy treatments, providing valuable insights for personalized medicine in oncology.