Recurrence after BCG therapy for non-muscle invasive bladder cancer (NMIBC) occurs in approximately 40% of the cases at 5 years. Understanding the mechanisms of action of intravesical BCG may help in improving treatment outcomes. We aim to describe changes in the tumor microenvironment upon BCG therapy and biomarkers associated with worse oncological outcomes.
Formalin-fixed and paraffin-embedded (FFPE) tissue sections before (Pre-BCG) and after (post-BCG) BCG therapy were obtained from our institutional biorepository and used for bulk targeted gene expression analysis. Tumor specimens for single cell RNAseq (scRNAseq) were analyzed fresh. Differential gene expression analysis was performed for both bulk targeted and scRNAseq data. P values from DESeq2 analysis were adjusted using the independent Hypothesis Weighting method. Kaplan Meier curves were created and compared based on median gene expression. P values were corrected using the Benjamini-Hoschberg false discovery rate procedure.
An upregulation of genes involved in B cell function was observed after BCG therapy. Pathway analyses revealed a significant enrichment in genes associated with switched memory B cells and a downregulation in genes associated with marginal zone B cells uniquely in post-BCG tumors. Additionally, there was a significant reduction in genes encoding PD-1, PD-L1, and PD-L2. IGHA1 expression was significantly enriched in tumors that recur ≥ 6 months compared to those that recur ≤ 6 months. Single-cell RNA sequencing analysis revealed the presence of B cell subsets at different maturation stages.
An upregulation of genes involved in B cell function was observed in the TME after BCG therapy. Pathway analyses revealed a significant enrichment in genes associated with switched memory B cells and a downregulation in genes associated with marginal zone B cells uniquely in post-BCG tumors. Additionally, there was a significant reduction in genes encoding PD-1, PD-L1, and PD-L2. IGHA1 expression was significantly enriched in tumors that recur ≥ 6 months compared to those that recur ≤ 6 months. Single-cell RNA sequencing analysis revealed the presence of B cell subsets at different maturation stages.
Gene expression analysis of the bladder tumor microenvironment reveals a novel B cell signature in NMIBC patients after treatment with M. bovis BCG
Category
Bladder Cancer > Non-Muscle Invasive Bladder Cancer
Description
Presented By: Jorge Daza
Authors: Jorge Daza
Bérengère Salomé
Yuanshuo Wang
Andrew Charap
Adam Farkas
Rachel Brody
Emilie Grasset
Giuliana Magri
Dominic D. LaRoche
Yong Lee
Rafael Cabal
Ketan Badani
Reza Mehrazin
Peter Wiklund
Matthew Galsky
Nina Bhardwaj
Amir Horowitz
John P. Sfakianos