Urogenital Microbiota:Potentially Important Determinant of PD-L1 Expression in Male Patients with Non-muscle Invasive Bladder Cancer

• Published in: BMC microbiology Vol. 22; no. 1; pp. 7 - 12
• Main Authors: Chen, Chunxiao, Huang, Zehai, Huang, Pengcheng, Li, Kun, Zeng, Jiarong, Wen, Yuehui, Li, Biao, Zhao, Jie, Wu, Peng
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 04.01.2022; BioMed Central; BMC
• Subjects: Adult; Aged; B7-H1 Antigen - metabolism; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bladder; Bladder cancer; Cancer; Care and treatment; Composition; Control; Diagnosis; Disease Progression; Gene sequencing; Genitourinary organs; Humans; Identification and classification; Immune escape; Immunohistochemistry; Invasiveness; Male; Males; Medical examination; Methods; Microbiota; Microbiota (Symbiotic organisms); Microorganisms; Middle Aged; Muscles; PD-L1; PD-L1 protein; Recurrence; Risk factors; rRNA 16S; Smoking; Species richness; Statistical analysis; Subgroups; Tobacco; Tumors; Urinary Bladder Neoplasms - metabolism; Urinary Bladder Neoplasms - microbiology; Urinary Bladder Neoplasms - pathology; Urinary Bladder Neoplasms - urine; Urogenital System - microbiology; Urogenital tract; China; Urogenital tract; PD-L1; Microbiota; Bladder cancer; Immune escape
• ISSN: 1471-2180; 1471-2180
• DOI: 10.1186/s12866-021-02407-8

Urogenital microbiota may be associated with the recurrence of bladder cancer, but the underlying mechanism remains unclear. The notion that microbiota can upregulate PD-L1 expression in certain epithelial tumors to promote immune escape has been demonstrated. Thus, we hypothesized that the urogenital microbiota may be involved in the recurrence and progression of non-muscle invasive bladder cancer (NMIBC) by upregulating the PD-L1 expression. To test this hypothesis, we investigated the relationship between urogenital microbial community and PD-L1 expression in male patients with NMIBC. 16S rRNA gene sequencing was performed to analyse the composition of urogenital microbiota, and the expression of PD-L1 in cancerous tissues was detected by immunohistochemistry. The subjects (aged 43-79 years) were divided into PD-L1-positive group (Group P, n = 9) and PD-L1-negative group (Group N, n = 19) respectively based on their PD-L1 immunohistochemical results. No statistically significant differences were found in the demographic characteristics between group P and N. We observed that group P exhibited higher species richness (based on Observed species and Ace index, both P < 0.05). Furthermore, subgroup analysis showed that the increase in number of PD-L1 positive cells was accompanied by increased richness of urogenital microbiota. Significantly different composition of urogenital microbiota was found between group P and group N (based on weighted Unifrac and unweighted Unifrac distances metric, both P < 0.05). Enrichment of some bacterial genera (e.g., Leptotrichia, Roseomonas, and Propionibacterium) and decrease of some bacterial genera (e.g., Prevotella and Massilia) were observed in group P as compared with group N. These findings indicated that these genera may affect the expression of PD-L1 through some mechanisms to be studied. Our study provided for the first time an overview of the association between urogenital microbiota and PD-L1 expression in male patients with NMIBC, indicating that urogenital microbiota was an important determinant of PD-L1 expression in male NMIBC patients.