Si-circRNA treatment caused a significantly higher fraction of NSCLC cells in the G2/M phase (20.02% in A549 and 33.77% in H1650) than in the NC cells (8.34% in A549 and 8.42% in H1650), whereas the fraction of cells in S phase was reduced (17.57% in A549 and 20.02% in H1650) compared with NC cells (27.77% in A549 and 46.38% in H1650), suggesting that downregulating circ-SEC31A might induce a G2/M arrest in NSCLC cells. The gene discussed is SEC31A; the disease is non-small cell lung carcinoma.