Prognostic role of stromal tumor-infiltrating lymphocytes in locally advanced upper tract urothelial carcinoma: A retrospective multicenter study (TSU-02 study)

Abstract

Locally advanced upper urinary tract urothelial carcinoma (UTUC) exhibits high recurrence and metastasis rates even after radical nephroureterectomy. Adjuvant immunotherapy can be a reasonable option, and a simple, low-cost, and effective biomarker is further needed. Stromal tumor-infiltrating lymphocytes (sTILs) has been demonstrated as a prognostic and predictive biomarker in various tumor types, but not yet in locally advanced UTUC. In this multicenter, real-world and retrospective study, we tried to investigate the prognostic role of sTIL and its correlation with the PD-L1/PD-1/CD8 axis by reviewing the clinicopathologic variables of 398 locally advanced UTUC patients at four high-volume Chinese medical centers. sTIL density was evaluated with standardized methodology on H&E sections, and patients were stratified by the cutoff of sTIL (50%). Results showed that high sTIL indicated improved survival (CSS, p = .022; RFS, p = .015; DFS, p = .004), and was an independent predictor of better CSS (HR, 0.577; 95% CI, 0.391-0.851; p = .006), RFS (HR, 0.613; 95% CI 0.406-0.925; p = .020) and DFS (HR, 0.609; 95% CI, 0.447-0.829; p = .002). A strongly positive correlation between sTIL density and the expression level of PD-1/PD-L1/CD8 axis was observed. We also found that aristolochic acid (AA) exposure was associated with increased sTIL and elevated PD-L1 expression, indicating that AA-related UTUC might be a distinct subgroup with unique tumor microenvironment characteristics. Our results show that sTIL can be an easily acquired biomarker for prognostic stratification in locally advanced UTUC.

Keywords: Stromal TIL; aristolochic acids; biomarker; locally advanced UTUC; pd-L1; prognosis.

Figure 1.

Study design and clinical cohorts. A total of 398 patients meeting the inclusion/exclusion criteria were included. Upper tract urothelial carcinoma = UTUC, Radical nephroureterectomy = RNU, Cancer-specific survival = CSS, Recurrence-free survival = RFS, Disease-free survival = DFS

Figure 2.

Expression of PD-L1/PD-1/CD8 in locally advanced UTUC. (a) Representative images of immunohistochemical detection of PD-L1 (brown) in tumor cells (TCs). (b, c) Representative images of immunohistochemical detection of CD8⁺ lymphocytes and PD-1⁺ lymphocytes (brown). (scale bar, 100 μm for upper rows, 25 μm for lower rows). Programed death-1 = PD-1, Programed death-ligand 1 = PD-L1

Figure 3.

Kaplan-Meier curves on patient survival by sTIL density. sTIL can predict (a) cancer-specific survival (p= .022), (b) recurrence-free survival (p= .015), and (c) disease-free survival (p = .004). P values were calculated by the log-rank test. Vertical tick marks represent censored subjects. Stromal tumor-infiltrating lymphocyte = sTIL

Figure 4.

Correlations between sTIL and PD-L1/PD-1/CD8 axis. (a) Correlation between sTIL and PD-L1⁺ TCs. (Pearson’s chi-squared test, p= .012). (b) Correlation between sTIL and CD8⁺ lymphocytes density. (Pearson’s correlation test, p = .017, r = 0.2604). (c) Correlation between sTIL and PD-1⁺ lymphocytes density. (Pearson’s correlation test, p = .005, r = 0.3039). (d) Representative images of CD8⁺ lymphocytes in low- or high-sTIL cases (scale bar, 50 μm). (e) Representative images of PD-1⁺ lymphocytes in low- or high- sTIL cases (scale bar, 50 μm). Programed death-1 = PD-1, Programed death-ligand 1 = PD-L1, Tumor cell = TC, Stromal tumor-infiltrating lymphocyte = sTIL, Immunohistochemistry = IHC, High-power field = HP

Figure 5.

Correlations between sTIL and AA-related UTUC. (a) Correlation between AA exposure and sTIL density (Pearson’s chi-squared test, p= .020). (b) Correlation between AA exposure and PD-L1 expression in TCs after PSM. (Pearson’s chi-squared test, p= .003). (c) Heat map of clinicopathologic factors in patients with or without AA exposure after PSM. Aristolochic acid = AA, Programed death-ligand 1 = PD-L1, Tumor cell = TC, Stromal tumor-infiltrating lymphocyte = sTIL, Propensity score matching = PSM