Molecular Profiling Reveals Immunosuppressive Tumor Immune Microenvironment in Primary versus Paired Asynchronous Metastatic Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is a highly immune infiltrated cancer, but how the tumor immune microenvironment (TIME) evolves during disease progression is unknown. Insights into heterogeneity within primary ccRCC raise questions about potential heterogeneity between primary and paired metastatic tumors. This information may improve understanding of immune evasion leading to metastatic disease and response to immunotherapy. In this study, we characterize and compare the TIME of primary ccRCC with paired asynchronous metastases. We demonstrate higher infiltration of immunosuppressive cells in the TIME of primary ccRCC compared with metastatic sites. Further studies are necessary to determine the prognostic and therapeutic significance of these findings. Understanding the heterogeneity of the tumor immune microenvironment in RCC, both intratumorally and between metastatic sites, has important clinical implications for selecting appropriate therapies and developing predictive biomarkers. Future research should focus on elucidating the impact of these findings on immunotherapeutic responses and patient outcomes in ccRCC. Overall design: Analysis of ccRCC patients who developed recurrence post radical nephrectomy and had both primary and metastatic tissue available. Whole-transcriptome sequencing was performed on formalin-fixed paraffin-embedded (FFPE) specimens using the illumina platform. Differential expression gene (DEG) analysis was performed using R package edgeR. Gene set enrichment analyses (GSEA) to identify hallmark pathway enrichment was performed using R package fgsea. TIME deconvolution was quantified using CIBEROSRT, an in silico flow cytometry tool.