TNF and hepatocellular carcinoma: Exosomal circUHRF1 derived from HCC degrades miR-449c-5p to upregulate TIM-3 expression, inhibiting the secretion of IFN-γ and TNF-α by NK cells, thereby impairing their antitumor function and contributing to anti-PD-1 therapy resistance (Zhang et al., 2020b).