Ribosome biogenesis‐based predictive biomarkers in endocrine therapy (Anastrozole) combined with mTOR inhibitor (Vistusertib) in endometrial cancer: translational study from the VICTORIA trial in collaboration with the GINECO group

Resistance of advanced hormone‐dependent endometrial carcinoma to endocrine therapy remains a worldwide clinical issue. We recently reported that the combination of Vistusertib (V, mTOR inhibitor) and Anastrozole (A, aromatase inhibitor) improves the progression‐free rate compared to Anastrozole alone. However, a better patient selection based on biomarkers would improve patient outcome. We evaluate for the first time the usage of ribosome biogenesis (RiBi) factors as a source of innovative markers. Using 47 FFPE tumours (A n = 18; V + A n = 29), 32 blood samples (A n = 13; V + A n = 19) and 30 samples of total RNAs (A n = 12; V + A n = 18) from the VICTORIA clinical trial, we observed an association between RiBi‐associated markers and drug activity or prediction of treatment response. NOP10 and NHP2 mRNA levels were significantly higher in non‐responders compared to responders in the Vistusertib + Anastrozole arm (P = 0.0194 and P = 0.0002 respectively; i.e. 8 weeks progression‐free survival as endpoint). This study provides RiBi‐based markers relevant for a better selection of patients with advanced endometrial carcinoma by predicting the response of endocrine therapy combined with mTOR inhibitor.