Immune checkpoint blockade (ICB) is currently the standard of care for metastatic renal cell carcinoma (RCC), but treatment responses remain unpredictable. Aristolochic acid (AA), a prevalent supplement additive in Taiwan, has been associated with RCC and induces signature mutations, although its effect on the tumor-immune microenvironment (TIME) is unclear. We aimed to investigate the immune profile of AA-positive RCCs and explore its potential role as a susceptible candidate for ICB. Tissue samples from 22 patients with clear cell RCC (ccRCC) were collected for whole-exome sequencing to determine the genetic features and AA mutational signature (the discovery cohort). The corresponding RNA was sent for NanoString PanCancer IO 360 gene expression analysis to explore the immunological features. The formalin-fixed, parafilm-embedded slides of ccRCCs were sent for multiplex immunohistochemistry/immunofluorescence stain using Vectra system to evaluate the TIME. Tissues from two patients with metastatic RCC demonstrating complete response to ICB were sent for studies to validate the findings (the index patients). The results showed that AA mutational signatures with high tumor mutational burden (TMB) were present in 31.81% of the tumors in the discovery cohort. Three distinct clusters were observed through NanoString analysis. Clusters 1 and 3 were composed mainly of AA-positive RCCs. Cluster 3 RCCs exhibited higher tumor inflammation signature scores and higher immune cell type scores. Vectra analysis revealed a higher percentage of CD15+ and BATF3+ cells in cluster 1, whereas the percentage of CD8+ cells was potentially higher in cluster 3. Strong AA mutational signatures were found in the tumors of two index patients, and both were grouped to cluster 3. In conclusion, AA may induce higher TMB and alter the immune microenvironment in RCCs, which makes the tumors more susceptible to ICB. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
The Journal of pathology. 2024 Oct 03 [Epub ahead of print]
Po-Hung Lin, Jason Yongsheng Chan, Peiyong Guan, Jing Han Hong, Abner Herbert Lim, Cedric Chuan-Young Ng, Joe Poh Sheng Yeong, Jing Yi Lee, Wei Liu, Jeffrey Chun Tatt Lim, See-Tong Pang, Bin Tean Teh
Division of Urology, Department of Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan., Cancer Discovery Hub, National Cancer Centre Singapore, Singapore, Singapore., Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore., Cancer and Stem Cell Biology Programme, Duke-NUS Medical School, Singapore, Singapore., Integrative Biology for Theranostics Lab, Cancer Signaling & Therapies Programme, Institute of Molecular and Cell Biology, Singapore, Singapore., Laboratory of Cancer Epigenome, Division of Medical Science, National Cancer Centre Singapore, Singapore, Singapore.