Hsa_circ_0081534 knockdown blocked tumor growth in vivo. (A) Tumor volume was measured every 7 days. (B, C) After 6 weeks, mice were sacrificed, and excised tumors were weighed. (D–F) Levels of hsa_circ_0081534, miR-508-5p, and FN1 were measured using qRT-PCR. (G) Hsa_circ_0081534 knockdown suppressed Ki-67 expression in mice. (H) Schematic diagram of the hsa_circ_0081534/miR-508-5p/FN1 axis in NPC progression. *P < 0.05.