PRF1 and hepatocellular carcinoma: Zoledronate induces the proliferation of γδ T cells in HCC patients who exhibit upregulated expression of IFN-γ, TNF-α, GrB, perforin, and lysosome-associated membrane protein 1 (47). A clinical trial has shown that the combined use of γδ T cells, NK cells, and cytokine-induced killer (CIK) therapy significantly inhibits virus replication and prolongs the survival rate of HCV-positive HCC patients (21).