A novel plasma circular RNA circFARSA is a potential biomarker for non‐small cell lung cancer

Abstract Emerging evidence indicates that circular RNA s (circ RNA s) are implicated in cancer development. This study aimed to evaluate whether circulating circ RNA s may serve as novel biomarkers for non‐small cell lung cancer ( NSCLC ). We used RNA sequencing ( RNA ‐seq) and quantitative real‐time PCR to explore cancer‐related circ RNA s. Bioinformatics and functional analyses were performed to reveal biological effects of circ RNA s on lung cancer cells. A total of 5471 distinct circ RNA s were identified by total RNA ‐seq, in which 185 were differentially expressed between cancerous and adjacent normal tissues. A circ RNA derived from exon 5–7 of the FARSA gene, termed circ FARSA , was observed to increase in cancerous tissues ( P = 0.016), and was more abundant in patients’ plasma than controls ( P < 0.001). Overexpression of circ FARSA in A549 cell line significantly promoted cell migration and invasion. In silico analysis suggested that circ FARSA might sponge miR‐330‐5p and miR‐326, thereby relieving their inhibitory effects on oncogene fatty acid synthase. Summarily, this study revealed circ RNA profile of NSCLC for the first time and provided the evidence of plasma circ FARSA as a potential noninvasive biomarker for this malignancy.