Abstract: Objective To explore the differential expression of circGAPVD1 derived from plasma exosomes in patients with colorectal cancer (CRC), and to analyze its potential as a diagnostic marker for colorectal cancer. Methods A total of 111 CRC patients who underwent surgical treatment and were pathologically confirmed at the Affiliated Hospital of Xuzhou Medical University from January 2022 to August 2023 were enrolled, along with 85 healthy individuals from routine physical examinations as controls. Plasma exosomes were isolated and characterized using transmission electron microscopy (TEM), Western blot and nano-particle size analysis. The expression level of circGAPVD1 was detected by RT-qPCR. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of circGAPVD1 for CRC. Results Compared with healthy controls, circGAPVD1 was significantly expressed higher in the plasma exosomes of patients with CRC(P＜0.01). The sensitivity of circGAPVD1 in the diagnosis was 77.5% with specificity as 76.5%. The area under ROC curve was 0.818 6,suggesting circGAPVD1 has robust diagnostic efficacy for CRC. In addition, related to the pathological data of patients with CRC, the lymph node metastasis and TNM staging showed a positive relation to high expression of circGAPVD1. Conclusions Plasma exosome-derived circGAPVD1 is a potential novel biomarker which support the clinical diagnosis of CRC.

Key words: colorectal cancer, exosome, circular RNA(circRNA), diagnostic marker