Abstract: Objective To investigate the characteristics of tumor immune microenvironment of TP53 mutant hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC).  Methods The living tissue samples and paired paracancerous tissue samples of 38 HCC patients who underwent hepatobiliary surgery in Hepatobiliary Surgery Department of Guangxi Medical University Cancer Hospital from 2018 to 2019 were collected, DNAs of tissues were extracted, and gene mutation was analyzed. Mass spectrometry flow cytometry (CyTOF) was used to compare the characteristics of the immune microenvironments in and between the cancer tissues and  paired paracancerous tissues of the TP53 mutated group and TP53 unmutated group. Results CyTOF was used to identify the immune cells in TP53 mutated group and TP53 unmutated group, and the results were identified as 22 cell subsets, including CD4⁺T-cell subsets, CD8⁺T-cell subsets, B-cell subsets, dendritic cell subsets, natural killer (NK) cell subsets, NKT cell subsets, granulocyte subsets and two unknown cell subsets. Among them, the expression ratio of CD8⁺T cells and CD4⁺T cells in TP53 mutated group was higher than that in TP53 unmutated group (2.26% vs 0.47%, P=0.028; 7.53% vs 3.55%, P=0.046). Conclusions The tumor immune microenvironment of TP53 mutant HBV-associated HCC has immune heterogeneity.

Key words: Hepatocellular carcinoma, Immune microenvironment, TP53 mutation, Mass spectrometry flow cytometry