Diagnostic value of plasma circular RNA based on droplet digital polymerase chain reaction in lung adenocarcinoma

Abstract Background Plasma circular (circ)RNAs detected by droplet digital polymerase chain reaction (ddPCR) may be ideal markers for liquid biopsy. However, ddPCR detection of circRNAs in plasma for diagnosis of lung adenocarcinoma has been rarely reported. Methods An RNA sequencing analysis was performed in plasma from patients with early lung adenocarcinoma and healthy individuals. Droplet digital PCR was used to verify the differentially expressed genes. Results The copy numbers of circle RNALZIC (circLZIC)and circle RNACEP350 (circCEP350) in the plasma of lung adenocarcinoma patients were significantly higher than in plasma of healthy people, and the copy numbers in postoperative plasma of the same patients were significantly lower than those in preoperative plasma. CircLZIC and circCEP350 alone and in combination had diagnostic value in lung adenocarcinoma and early lung adenocarcinoma. CircLZIC and circCEP350 had more binding sites with multiple microRNAs. Their target genes were enriched in several signaling pathways. Conclusion The copy numbers of circLZIC and circCEP350 were higher in plasma of lung adenocarcinoma patients than in plasma of healthy controls, significantly correlated with tumor size and TNM stage, and closely related to the occurrence and development of tumors. These circRNAs may serve as molecular markers for the diagnosis of lung adenocarcinoma.