T lymphocyte-based immune response and therapy in hepatocellular carcinoma: focus on TILs and CAR-T cells

Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related death worldwide. The primary therapies for HCC are liver transplantation, hepatic tumor excision, radiofrequency ablation, and molecular-targeted medicines. An unfavorable prognosis marks HCC and has limited pharmacological response in therapeutic studies. The tumor immune microenvironment (TME) imposes significant selection pressure on HCC, resulting in its evolution and recurrence after various treatments. As the principal cellular constituents of tumor-infiltrating lymphocytes (TILs), T cells have shown both anti-tumor and protumor actions in HCC. T cell-mediated immune responses are pivotal in cancer monitoring and elimination. TILs are recognized for their critical involvement in the progression, prognosis, and immunotherapeutic management of HCC. Foxp3 + , CD8 + , CD3 + , and CD4 + T cells are the extensively researched subtypes of TILs. This article examines the functions and processes of several subtypes of TILs in HCC. Emerging T cell-based therapies, including TILs and chimeric antigen receptor (CAR)-T cell therapy, have shown tumor regression in several clinical and preclinical studies. Herein, it also delves into the existing T cell-based immunotherapies in HCC, with emphasis on TILs and CAR-T cells.