GCC2 in Small Extracellular Vesicles as a Diagnostic and Prognostic Biomarker of Early‐Stage Lung Adenocarcinoma

Emerging evidence suggests that GRIP and coiled-coil domain-containing two enriched small extracellular vesicles (sEV-GCC2) may serve as diagnostic biomarkers of early-stage lung adenocarcinomas. However, the roles of these molecules remain unclear. This study evaluated the diagnostic and prognostic potential of sEV-GCC2 for detecting early-stage lung adenocarcinoma and its tumourigenic role in vitro and in vivo. This retrospective multicentre study analyzed 470 plasma samples (320 lung adenocarcinoma patients, 150 controls; mean follow-up: 34.7 ± 24.0 months) across five institutions. Size-exclusion chromatography and enzyme-linked immunosorbent assay were used to measure sEV-GCC2 levels, whereas immunohistochemistry was used to confirm GCC2 expression in tumour tissues. Functional studies were performed using the PC9 and H1650 lung adenocarcinoma cell lines in vitro and the corresponding PC9-based preclinical models in vivo to evaluate the tumour-related effects of sEV-GCC2. Patients exhibited significantly elevated sEV-GCC2 levels compared to controls (area under the receiver operating characteristic (ROC) curve [AUC]: 0.904, P < 0.001), with similar results in stage TisN0-T1miN0 disease (AUC: 0.781, P < 0.001). sEV-GCC2 levels were associated with the pathological TNM stage and tumour location. Higher sEV-GCC2 levels were correlated with poorer recurrence-free survival (RFS), overall survival and recurrence rates, even in patients with stage 0-IA1 disease. Functional studies have revealed that sEV-GCC2, but not GCC2-deficient sEVs, promote cancer cell proliferation, tumour growth and lymph node metastasis in vitro and in vivo. These findings highlight the diagnostic and prognostic potential of sEV-GCC2 and its tumourigenic role in early-stage lung adenocarcinoma. This study was registered at ClinicalTrials.gov (NCT04529915).