Tumor-infiltrating CD8+ T cells as a biomarker for chemotherapy efficacy in unresectable hepatocellular carcinoma

Atezolizumab plus bevacizumab and lenvatinib are approved frontline therapies for advanced hepatocellular carcinoma (HCC). Patients with advanced HCC continue to have a poor prognosis despite these therapeutic choices. Previous studies have reported CD8(+) tumor-infiltrating lymphocytes (TILs) as a biomarker to predict responsiveness to systemic chemotherapy. The present study investigated whether evaluating CD8(+) TILs by immunohistochemistry staining of liver tumor biopsy tissues could help predict the response of patients with HCC to atezolizumab plus bevacizumab and lenvatinib. In total, 39 patients with HCC who underwent liver tumor biopsy were classified into high and low CD8(+) TILs groups and were then divided by therapy type. The clinical responses to treatment in both groups were evaluated for each therapy. There were 12 patients with high-level CD8(+) TILs and 12 patients with low-level CD8(+) TILs among those who received atezolizumab plus bevacizumab. An improved response rate was observed in the high-level group compared with the low-level group. The high-level CD8(+) TILs group had a significantly longer median progression-free survival compared with the low-level group. Among the patients with HCC who received lenvatinib, five had high-level CD8(+) TILs and 10 had low-level CD8(+) TILs. There were no differences in response rate or progression-free survival between these groups. Although the present study included only a limited number of patients, the findings suggested that CD8(+) TILs could be a biomarker for predicting response to systemic chemotherapy in HCC.