This study examined CD8+ cell distribution in hepatocellular carcinoma (HCC) and peritumoral liver tissue to investigate the overall survival (OS) and recurrence-free survival (RFS). It is well understood that CD8+ lymphocytes are involved in both the anti-tumor response and in managing hepatocyte damage in the parenchyma. Further, it was previously known that HCC often develops following long-term inflammatory liver disease.

CD8 immunostaining of liver tissue from HCC surgical resection samples was analyzed using digital pathology. Specifically, the HCC-stroma interface and the perineoplastic liver parenchyma-stroma interface were examined utilizing a combination of HALO®, HALO AI, and custom computational analyses.

H&E and CD8 immunohistochemistry (IHC) slides were scanned on an Aperio AT2 DX scanner and a pathologist manually annotated the largest continuous malignant and non-malignant area on each slide. HALO AI was trained to segment tissue into hepatocytes (malignant and non-malignant), stroma, and background/debris classes. The Multiplex IHC module of HALO was used to quantify CD8 positivity on the IHC slides. Spatial analysis of the distribution of CD8+ cells was performed using a hexagonal grid-based computational method developed by the authors in a 2020 study.

The authors assessed the prognostic value of the CD8+ distribution alongside clinical factors such as duration of surgery and peripheral blood testing results. One of the independent predictors of worse OS included a low standard deviation of CD8+ density at the tumor edge, which is a measure of spatial heterogeneity of the densities along the interface. Additional independent predictors of worse OS included long surgery duration and a high average CD8+ density in the epithelial portion of the perineoplastic liver-stroma interface.

The authors created a combined prognostic score of 5-year OS probability and stratified patients into three categories of 76%, 40%, and 8%. Factors that predicted longer RFS included wider tumor-free margin and a higher mean CD8+ density in the epithelial portion of the tumor-stroma interface.

The authors conclude that the CD8+ density at the interface of the stroma and the malignant or non-malignant epithelium have opposite prognostic impacts for HCC and peritumoral liver tissue and that patient outcomes after liver resection can be modeled by combining surgical, laboratory, and pathological data.