ALK and neoplasm: We separately analyzed the relationship between the expression of hsa_circ_0006423 and clinicopathological factors (i.e., gender, age, smoking history, histology, tumor location, differentiation, tumor size, TNM stage, driver gene, epidermal growth factor receptor [EGFR], anaplastic lymphoma kinase [ALK] and programmed cell death-ligand 1 [PD-L1]) of patients with NSCLC before surgery.