Analysis of Regulatory T-cells-specific mRNAs for Improving Prognosis, Immunotherapy Response and Therapeutic Resistance of Patients With Prostate Cancer

Background: Prostate cancer recognized as a “cold” tumor has an immunosuppressive microenvironment in which regulatory T-cells (Tregs) usually represent a major role. Therefore, identifying a prognostic signature of Tregs has promising benefits of improving survival of prostate cancer patients. However, the prognostic signature based on Tregs-specific mRNAs for prostate cancer is lacking. Methods: We systematicly analyzed transcriptional profiles of Tregs and 19 other immune cell types using 42 purified immune cell datasets from GEO to identify Tregs-specific mRNAs, and develop and validate a prognostic signature of Tregs (named “TILTregSig”) for monitoring prognosis of prostate cancer using TCGA and ICGC datasets. We also applied the signature to five immunotherapy response datasets and GSCALite to analyze the potential of the TILTregSig for predicting CIT response and cancer therapeutic resistance.Results: We develop the TILTregSig comprising five mRNAs (SOCS2, EGR1, RRM2, TPP1 and C11orf54) for prostate cancer patients. We find that the TILTregSig is a stronger predictor for tumor immunity compared with tumor mutation burden (TMB) and glycolytic activity which have been reported as immune predictors. Further analyses indicate that the TILTregSig may influence tumor immunity mainly by mediating tumor-infiltrating Tregs. Moreover, the TILTregSig also shows promising potential for predicting cancer immunotherapy (CIT) response and therapeutic resistance in multiple cancers.Conclusions: Our study has highlighted the value of the TILTregSig as a prognostic biomarker of prostate cancer from a tumor-infiltrating Tregs perspective, and strengthened its potential application as predictor of CIT response and cancer therapeutic resistance, which warrants further.