Ribosomal protein S26 (RPS26) expression of advanced cervical cancer (CC) to predict response to programmed death-1 inhibitor combination therapy: A secondary analysis of the CIBI308ALTER-C201 trial.

Abstract

e17520 Background: PD-1 inhibitor combination therapy is widely used in cervical cancer, and improves prognosis. However, there is still a lack of effective predictive markers. The results of previous single-cell analysis of cervical cancer in our research group suggested that RPS26 is related to changes in the immune microenvironment. The purpose of this study is to evaluate whether RPS26 can be used as a prognostic marker for cervical cancer PD-1 inhibitor combination therapy. Methods: A total of 36 patients with CC were recruited. 18 patients were from CIBI308ALTER-C201 trail，and the other 18 were not. All patients underwent next-generation sequencing (NGS). Tumor RPS26 expression was assigned by immunohistochemistry as follows: 0, 1+, 2+, 3+. Significant difference was tested by Fisher's exact test. Kaplan-Meier analysis were applied for survival analysis. Results: The PFS of patients from CIBI308ALTER-C201 trail was significantly longer among patients with RPS26 expression for 2+/3+ than 0/1+ (not reached v 9.877 months, p= 0.0497). There were 11, 14, 9 and 2 patients with RPS26 expression of 0, 1+, 2+, and 3+, respectively. There were 12 and 24 for PIK3CA mutant patients and wild-type, respectively. There was no patient with RPS26 expression for 0 in the PIK3CA mutant group, and 9 patients with RPS26 expression for 0 in the PIK3CA wild group. The expression of RPS26 was significantly different between the two groups ( p= 0.0163). Conclusions: Our study suggested that RPS26 could be novel predictive biomarkers in patients with CC treated with PD-1 inhibitor combination therapy, and PIK3CA mutation enhances RPS26 expression in CC.