Influence of Intratumor Microbiome on Clinical Outcome and Immune Processes in Prostate Cancer

Area of Science:

• Microbiome research
• Cancer biology
• Prostate cancer (PC) research

Background:

• Prostate cancer (PC) affects 1 in 9 American men, but most cases are indolent.
• A subset of PC patients develop metastatic and fatal disease.
• The role of the intratumor microbiome in PC progression remains unclear.

Purpose of the Study:

• To analyze intratumor bacterial compositions in PC.
• To determine the influence of the microbiome on metastatic PC growth.
• To identify specific microbes that deter or contribute to PC aggressiveness.

Main Methods:

• Analysis of large-scale RNA-sequencing data and clinical data from PC patients.
• Correlation of microbial abundance with immune pathways and PC risk factors.
• Identification of specific microbes associated with tumor aggressiveness.

Main Results:

• Most identified intratumor microbes exhibited anti-tumor roles in PC.
• Anti-tumor microbes (e.g., Listeria monocytogenes, Methylobacterium radiotolerans) were overrepresented in tumors.
• Specific microbes were negatively correlated with Gleason score, TNM stage, PSA, and AR expression.
• Other microbes were positively correlated with genomic alterations, immune-associated genes, and prostate cancer stem cell genes.

Conclusions:

• Intratumor microbes may play a significant role in modulating PC progression.
• Certain microbes may mitigate tumor growth by recruiting immune cells.
• Other microbes may contribute to PC aggressiveness and metastasis.