Fig. 4

Increasing intratumoral and stromal CD8+ T-cell densities in ICC are correlated with worse OS and DFS. Association of OS and DFS with the CD8+ T-cell density within tumors (A, B) and in the stroma (C, D). Probabilities of overall and disease-free survival were estimated using the Kaplan–Meier method and compared using the log-rank statistics or the Cox proportional hazards regression model. The upper quartile was used as the breakpoint for the stromal CD8+ T-cell density, and the approximate lower and upper quartiles were used for the tumor CD8+ T-cell density. The reported HRs for the intratumoral CD8+ T-cell density reflect the survival comparison between tumors with a high density (≥ 40 CD8+ T cells/Hp) and those with a low density (< 40 CD8+ T cells/Hp)