Macrophage Phenotype in Combination with Tumor Microbiome Composition Predicts RCC Patients' Survival: A Pilot Study

Area of Science:

• Oncology
• Microbiology
• Immunology

Background:

• Identifying novel prognostic markers for renal cell carcinoma (RCC) is crucial in urology.
• The roles of tumor microbiome and stromal inflammation in RCC prognosis are not well understood.

Purpose of the Study:

• To investigate the prognostic significance of the tumor microbiome and stromal inflammatory markers in RCC.
• To explore the relationship between bacterial burden, immune cell infiltration, and patient outcomes in RCC.

Main Methods:

• Analyzed tumor and normal kidney tissue from 66 RCC patients using 16S rRNA amplicon sequencing for microbiome profiling.
• Characterized tumor stroma using immunohistochemistry to quantify PU.1+ macrophages and CD66b+ neutrophils.
• Correlated microbiome data with stromal cell content and clinical outcomes.

Main Results:

• Significant differences in alpha diversity were observed between normal kidney tissue and all RCC subtypes.
• Bacterial burden was higher in adjacent normal tissue compared to tumor tissue.
• A significant correlation was found between bacterial burden and the content of PU.1+ macrophages and CD66b+ neutrophils.
• Tumors with high PU.1+ and CD66b+ cell content had lower bacterial burden.
• High bacterial burden in tumors was associated with a poor prognosis, particularly when combined with high PU.1+ and CD66b+ cell counts.

Conclusions:

• The study highlights the prognostic potential of analyzing both the tumor microbiome and stromal inflammatory cells in RCC.
• Combined analysis of bacterial burden and specific immune cell infiltration may offer novel biomarkers for predicting RCC patient prognosis.