Expression of ARID1B Is Associated With Poor Outcomes and Predicts the Benefit from Adjuvant Chemotherapy in Bladder Urothelial Carcinoma

Background ARID1B, which exists as a mutually exclusive isoform with ARID1A in the SWI/SNF chromatin remodeling complex, has been recently identified as a major mutant gene in a wide variety of cancers. The present study aimed to determine the association between ARID1B expression and outcomes, as well as the benefit from adjuvant chemotherapy in patients with bladder cancer. Methods Tissue microarrays of 143 consecutively recruited patients with bladder cancer from our center were created. Immunohistochemistry was performed to assess the expression of ARID1B and its association with outcomes. Clinicopathological factors were also evaluated. Results ARID1B expression was significantly associated with tumor size (P=0.015), T stage (P=0.027), lymph node status (P=0.030), TNM stage (P=0.040), overall survival (P<0.001), and progression-free survival (P=0.043). Furthermore, high expression of ARID1B was an independent indicator of poor OS (P=0.022). The prognostic model containing ARID1B showed a better predictive accuracy than the bench models. Most importantly, the benefit of adjuvant chemotherapy observed in patients with low ARID1B expression was superior to that observed in patients with high ARID1B expression. Conclusions Our study suggests that ARID1B can serve as a prognostic biomarker of bladder urothelial carcinoma. Additionally, ARID1B might be a predictive marker for selecting patients for adjuvant chemotherapy in the high-risk subgroup.