Abstract

Background Circular RNAs (circRNAs) derived from exosomes are involved in the carcinogenesis and development of non-small cell lung cancer (NSCLC), showing great potential to be diagnostic biomarkers for NSCLC. Methods Serum exosomes were isolated with an exosome isolation kit, and verified by western blot, transmission electron microscopy and a potentiometric analyzer. Five differentially expressed exosomal circRNAs, including hsa_circ_0069313, hsa_circ_0063526, hsa_circ_0010522, hsa_circ_0048677 and hsa_circ_0001946, were selected based on the circRNA array analyses and the published documents in Pubmed. The serum and serum exosomal levels of the above five circRNAs were quantified by qRT-PCR. The diagnostic power of serum and serum exosomal hsa_circ_0069313 was evaluated by receiver operating characteristic (ROC) test. Results The levels of hsa_circ_0069313 in serum exosomes were statistically lower than those in the matched serum samples. In contrast, the levels of hsa_circ_0063526, hsa_circ_0010522, hsa_circ_0048677 and hsa_circ_0001946 showed no statistical difference in the sera and serum exosomes of healthy donors. The levels of serum and serum exosomal hsa_circ_0069313 were notably elevated in the NSCLC group compared to the healthy, pneumonia and benign lung tumor groups. Furthermore, serum and serum exosomal hsa_circ_0069313 could differ benign lung tumor and NSCLC with AUC values of 0.803 and 0.749, respectively. Intriguingly, the higher levels of serum exosomal hsa_circ_0069313 were associated with stage III-IV, lymph node metastasis and distant metastasis of NSCLC. Conclusions Serum and serum exosomal hsa_circ_0069313 have the potential to discriminate NSCLC and benign lung tumor. The higher levels of serum exosomal hsa_circ_0069313 are linked to more aggressive pathological features of NSCLC.