Abstract
Background: CD103+CD8+ tissue-resident memory T (TRM) cells, associated with better overall survival among various malignancies, are thought to activate anti-tumour immune response and affect therapeutic sensitivity including both immunotherapy and adjuvant chemotherapy (ACT). Methods: Totally 650 muscle-invasive bladder cancer (MIBC) patients from three independent cohorts were included in this study for survival and cisplatin-based ACT response analysis. Another public data set consisting of 195 patients from IMvigor210 trial receiving PD-L1 blockade were involved in the assessment of immunotherapeutic response. Fifty-nine fresh tumour tissues were used to evaluate immune infiltration of CD103+CD8+ TRM cells. Results: Patients with high CD103+CD8+ TRM cells infiltration, but not CD8+ T cells, are more likely to benefit from immunotherapy and ACT. The presence of TRM cells is highly associated with an enhanced IFNγ-enriched and T cell-inflamed anti-tumour microenvironment. Elevated CD103+CD8+ TRM cells infiltration correlated with superior ACT response in mismatch repair (MMR), homologous recombination (HR), PIK3CA/AKT and RAS/RAF pathway proficient or histone modification and cell cycle pathway deficient patients. Conclusions: CD103+CD8+ TRM cells played a crucial role in anti-tumour immunity and served as an ideal prognostic biomarker. It could be treated as a superior companion predictor for treatment response to PD-L1 inhibitor and ACT within MIBC patients.