Background: Within the tumor microenvironment (TME), infiltrating lymphocytes and myeloid cells including tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) are key players involved in liver cancer progression. The purpose of the study was to explorer whether distinct infiltrated immune cell features differentially affect clinical outcome in hepatocellular carcinoma (HCC). 

Methods: We obtained respectable stage II HCC specimens, along with adjacent para-tumor tissues from 221 patients who underwent surgical resection at Eastern Hepatobiliary Surgery Hospital, (in Shanghai, China) from 2015 through April 2018. CD8+, CD163+ and CD66B+ tumor-infiltrating lymphocytes (TILs) in the cancer area (CA) and stroma area (SA), as well paratumor stroma area, were analyzed by multiple immunohistochemistry. 

Results: Hierarchical clustering analysis of immune cell densities revealed that all HCC samples can be classified into three distinct groups. The three immune oncology types (IO-types) were characterized by a strong CD8 T cell density in CA and SA region (IO-1), an intermediate state of CD8 and CD163+ (IO-2), and a strong CD163+ macrophage density in IO-3. Remarkably increasing risks of mortality and recurrence, as well as elevated AST, ALP, GGT and AFP levels, were identified in IO-3 group, when compared with IO-1 group. We then identified that percentages of CA-CD8+ TILs in the tumor sample and SA-CD163+ macrophages in the para-tumor region showed opposite distribution pattern among the three IO types, suggesting a predictive role for CD8/TAM ratio in HCC cohort. Therefore, we next classified all HCC samples into two subgroups, according to the levels of tumor-CA-CD8/paratumor-SA-CD163 ratio. Expectedly, higher rate of CD8/CD163 represented significantly improved overall survival (OS) and progression free survival (PFS), verses lower rate of CD8/CD163. Further association studies suggested that the two subgroups correlated with HBV DNA, tumor size, and microvascular invasion (MVI). Of note, a prognostic signature combining portal vein tumor thrombus (PVTT) and CD8/CD163 ratio discriminated HCC patients into four subtypes with increasing risk of mortality and recurrence. 

Conclusions: The current results indicated that the CD8/CD163 is a novel, independent prognostic factor for a lower rate of disease recurrence and favorable OS in patients with resectable HCC.