This study aims to construct the stromal immunotype, which could improve the prediction of postsurgical survival and adjuvant platinum-based chemotherapy in muscle-invasive bladder cancer (MIBC). A total of 118 patients with MIBC from Shanghai Cancer Center, 140 patients with MIBC from Zhongshan Hospital, and 287 patients with MIBC from TCGA cohort were included in the study. Immune cell infiltration was evaluated by IHC staining or CIBERSORT method. Five immune features were selected out of 22 immune features to construct immunotypes based on the LASSO Cox regression model. Using the LASSO model, we classified patients with MIBC into stromal immunotype A subgroup (CTLNKTregMacrophageMC) and stromal immunotype B subgroup (CTLNKTregMacrophageMC). Significant differences were found between immunotype A and immunotype B in the combined cohort with 5-year overall survival (OS, 76.0% vs. 44.0%; < 0.001) and 5-year disease-free survival (DFS, 62.8% vs. 48.3%; < 0.001). Stromal immunotype was revealed to be an independent prognostic indicator in multivariate analysis in all cohorts separately. Either OS or DFS was not improved by adjuvant chemotherapy (ACT) in pT2 stage patients or pT3+pT4 patients, but further analysis revealed that OS and disease-free was significantly improved by ACT in pT3+pT4 patients ( = 0.016 and = 0.006, respectively). Finally, stromal immunotype A showed higher immune checkpoint molecules (PD-L1, PD-1, and CTLA-4) expression. The stromal immunotypes could effectively predict survival and recurrence of MIBC. Furthermore, the immunotypes might be a practical predictive tool to identify pT3+pT4 patients who would benefit from ACT. .

No abstract

Which subgroups patients with muscle-invasive bladder cancer (MIBC) could benefit most from adjuvant chemotherapy (ACT) is blurred. Here we tried to stratify MIBC patients with tumor infiltrating mast cells (TIMs), explore the prognostic and predictive value of TIMs, and provide possible cellular explanations. We selected 259 MIBC patients who underwent radical cystectomy from two independent clinical centers between 2002 and 2014. TIMs were evaluated and prognostic and predictive value was assessed. The CIBERSORT method, Gene Set Enrichment Analysis (GSEA) and differential gene expression analyses were performed to explore the possible cellular mechanisms. TIMs infiltration was distinct between stromal and epithelial area of MIBC specimens. Patients with higher stromal TIMs had a significant worse overall survival and recurrence free survival (HR = 2.228, 95%CI: 1.467-3.550; P = 0.001 and HR = 1.984, 95%CI: 1.105-3.374; P = 0.016). More importantly, pT2 patients with low stromal TIMs tended to have a lower risk of death and recurrence after ACT (HR = 0.233, 95%CI: 0.020-0.814; P = 0.033 and HR = 0.180, 95%CI: 0.022-0.722; P = 0.031). A negative correlativity between TIMs and CD8 + T cells was identified on TCGA-BLCA cohort. Immunohistochemistry results validated that high stromal TIMs were negatively correlated with CD8 + T cells (Spearman's rho =-0.215, P < 0.001). Differential gene expression suggested that low TIMs might represent a state of immune activation in MIBC. To conclude, high stromal TIMs infiltration was an independent unfavorable prognosticator for MIBC patients. Patients with low stromal TIMs might benefit the most from ACT, especially in pT2 stage.