The significance of urine extracellular vesicle DNA methylation detection in the diagnosis and classification of prostate cancer

Introduction

As one of the most common malignant tumors in men, prostate cancer (PCa) still lacks convenient, non-invasive and highly specific diagnostic markers. The advantages of Extracellular vesicle (EV) DNA in tumor diagnosis have gradually attracted the attention of researchers. However, methylation detection, which is more advantageous than mutation detection in tumor diagnosis, has not been widely practiced in EV DNA, and its value in PCa diagnosis also remains underexplored.

Objectives

This study aims to establish and optimize an EV DNA methylation detection system and evaluate its diagnostic and classification potential for PCa.

Methods

We characterized EV DNA biological properties, optimized pretreatment strategies, validated its correlation with genomic DNA methylation, and explored urine EV DNA methylation targets in 86 benign prostatic hyperplasia (BPH) and 109 PCa patients across three cohorts (screening: 30 BPH/33 PCa; training: 27 BPH/30 PCa; validation: 29 BPH/46 PCa).

Results

Heterogeneous biological characteristics were observed among DNA from different subtypes of EV, but methylation profiles remained consistent across subtypes and post-DNase I treatment. EV DNA accurately reflected the methylation state of source cell genomic DNA. By combining our screening results with data from the TCGA database and previously reported, we developed a panel consisting of 667 PCa-specific methylation targets for detection. Among these, six methylation sites (MACF1、LINC01359-1、LINC01359-2、ADCY4、GAPLINC、C19orf25) demonstrated high diagnostic value for PCa, enabling construction of PCa and aggressive PCa differential diagnosis model with AUCs up to 0.74 and 0.91 respectively. The diagnostic value of these six markers was further confirmed using methylight PCR in the validation cohort which also displayed promising performance as a tool for diagnosing PCa.

Conclusion

This study highlights the potential of urine EV DNA methylation as a novel diagnostic marker for PCa and lays a foundation for future EV DNA research.