The predictive value of tumor infiltrating leukocytes in Hepatocellular Carcinoma: A systematic review and meta-analysis

For Hepatocellular carcinoma (HCC) surgery either through resection or transplantation often provides the only chance for cure. Since hepatocarcinogenesis and postsurgical prognosis is not only dependent on cirrhosis but also on immune activation and exhaustion, many studies have investigated tumor infiltrating leukocyte (TIL) subsets. This systematic review and meta-analysis aims at describing the cell groups and their predictive power regarding overall (OS), disease free (DFS) and recurrence free survival (RFS). A systematic search of the PubMed database was conducted (PROSPERO 172324). Data on CD3+, CD8+, Treg, B cells, macrophages, neutrophil and NK-cells were collected from Pubmed and related references up to December 2018. Overall (OS), disease-free (DFS) and recurrence free survival (RFS) in dependence of high vs. low infiltration rates were compared using a random effects meta-analysis. Altogether data from 3541 patients enrolled in 20 publications were included. Except for Tregs and Neutrophils, heterogeneity analysis was found to be moderate to high across the studies. High CD3+, CD8+, NK-cell infiltration predicted better survival (OS, DFS and RFS; p