Fig 2: Association between S100A9 expression and prognosis of HCC patients in the TCGA-LIHC database. (A) Violin plot showing the differential expression of the S100A9 gene in tumor (n = 365) or nontumor (n = 50) tissues from the TCGA-LIHC database; the Mann- Whitney test was used to analyze the nonparametric test between the two groups. HCC patients in the TCGA dataset were divided into two groups according to the median value of S100A9 expression (B) or minimum P-value approach (C). The prognostic value of S100A9 was evaluated by the Kaplan-Meier method, and examined by the log-rank test. (D) Top 30 GO enrichment results of the 3493 genes highly expressed in the S100A9high group. (E–H) Top enriched signaling pathways based on S100A9 expression identified by GSEA.

Fig 3: S100A9 expression in HCC tumor. (A) Representative images of IHC staining. (B) Scatter plot illustrating the correlation between S100A9-expressing cell counts in HCC by computer counting and investigator counting. (C) Quantification of S100A9+ cell densities in the N (nontumoral) and T (tumoral) regions (n = 382), and the Wilcoxon matched-pairs signed-rank test was used to analyze the nonparametric test between the paired two groups.

Fig 4: Prognostic value of S100A9+ cell in HCC patients. A high S100A9+ cell density in nontumor or tumor tissue was associated with poor OS (A, C) and a high recurrence rate (B, D) in HCC patients. Forest plots showing the association between S100A9 expression in tumors and clinicopathological features in HCC patients using univariate (E) or multivariate analysis (F). Patients were divided into two groups according to the median value of the S100A9+ cell density in nontumoral and tumoral tissues. The cumulative OS (G) and recurrence (H) times were calculated using the Kaplan-Meier method and then analyzed with the log-rank test.

Fig 5: Characterization of patient-derived S100A9+ cells. Multiple immunofluorescence staining shows DAPI (gray), S100A9 (green), CD34 (blue, A), CD56 (pink, D), CD20 (purple, G), and CD3 (orange, J) expression and coexpression (double-positive cells) in HCC tissue. Quantification of CD34 (B), CD56 (E), CD20 (H), and CD3 (K) cell densities in the T and N regions. (C) The percentages of S100A9+CD34+ cells among the total CD34+ cells in the N and T regions. (F) The percentages of S100A9+CD56+ cells among the total CD56+ cells in the N and T regions. (I) The percentages of S100A9+CD20+ cells among the total CD20+ cells in the N and T regions. (L) The percentages of S100A9+CD3+ cells among total CD3+ cells in the N and T regions (n = 4 - 7). Scale bar = 50 µm. The results are the means ± SEM (bars); NS, no significance; ND, not detected.