YAP1 activation is associated with the progression and response to immunotherapy of non-muscle invasive bladder cancer

Despite the availability of several treatments for non-muscle-invasive bladder cancer (NMIBC), many patients are still not responsive to treatments, and the disease progresses. A new prognostic classifier can differentiate between treatment response and progression, and it could be used as a very important tool in patient decision-making regarding treatment options. In this study, we focused on the activation of Yes-associated protein 1 (YAP1), which is known to play a pivotal role in tumour progression and serves as a factor contributing to the mechanism of resistance to various relevant therapeutic agents. We further evaluated its potential as a novel prognostic agent. We identified YAP1-associated gene signatures based on UC3-siYAP1 cells (n=8) and NMIBC cohort (n=460). Cross-validation was performed using 5 independent bladder cancer patient cohorts (n=1006). We also experimentally validated the changes of gene expression levels representing each subgroup. The 976-gene signature based on YAP1-activation redefined three subgroups and had the benefits of Bacillus Calmette-Guérin (BCG) treatment in patients with NMIBC (hazard ratio 3.32, 95% CI 1.29-8.56, p = 0.01). The integrated analysis revealed that YAP1 activation was associated with the characterization of patients with high-risk NMIBC and the response to immunotherapy. This study suggests that YAP1 activation has an important prognostic effect on bladder cancer progression and might be useful in the selection of immunotherapy. A funding list that contributed to this research can be found in the Acknowledgements section.