Tetraspanin-10 as a Potential Marker for Disease-Associated Extracellular Vesicles

This exploratory study introduces the concept of disease-associated Extracellular Vesicles (EVs), defined as EVs secreted under pathological conditions, and identifies a potential molecular marker for their characterization. However, disease-associated EVs constitute only a small fraction of circulating EVs, making their selective isolation and characterization a critical challenge. Identifying specific surface markers is essential for isolating these vesicles and advancing both fundamental EV biology research and clinical applications.It is valuable to analyze EVs that are derived directly from pathological tissues, rather than the heterogeneous EVs in the blood. A comprehensive proteome of tissue-exudative EVs (Te-EVs) obtained from the culture supernatant of freshly resected colorectal cancer tissues has been reported. We used this EV proteome dataset to identify candidates for novel EV surface marker specific to disease-associated EVs in cancer. We screened multi-pass membrane proteins that were suitable for immunoaffinity EV isolation and discovered that Tetraspanin-10 (TSPAN10) was specific to cancer Te-EVs.As a result of referring to RNA sequencing published by The Cancer Genome Atlas and FANTOM5, the physiological expression of TSPAN10 was localized to the retina, while almost all cases of solid tumor expressed TSPAN10 mRNA. In colorectal cancer, TSPAN10 mRNA expression was significantly associated with tumor stage and prognosis.We evaluated the diagnostic potential of TSPAN10 using serum from patients with colorectal cancer. TSPAN10 signals measured by enzyme-linked immunosorbent assay increased in a stage-dependent manner and demonstrated favorable diagnostic potential with 83% sensitivity and 84% specificity. Transmission electron microscopy showed the membrane localization of TSPAN10 on an EV derived from a patient with advanced colorectal cancer.TSPAN10-expressing EVs may represent a subset of disease-associated EVs, offering diagnostic utility and advancing biological insights into EVs in cancer and other pathological conditions.