In summary, our findings show that circPTK2 (hsa_circ_0008305) inhibits TGF-β-induced EMT through regulating TIF1γ and NSCLC cell metastasis, as well as establish a positive relationship between TIF1γ and circPTK2 in NSCLC, revealing a novel mechanism by which circRNA regulates TGF-β-mediated EMT and tumor metastasis, and suggesting that overexpression of circPTK2 could provide a therapeutic strategy for advanced NSCLC. The gene discussed is TRIM33; the disease is neoplasm.