三種不同尿液檢體應用於新型攝護腺癌PCA3早期篩檢試劑之比較

陳冠甫¹、林子平^1,2、黃志賢^1,2

¹臺北榮民總醫院泌尿部；²國立陽明交通大學醫學院泌尿學科及書田泌尿科學研究中心

Comparison between 3 different specimens for a novel PCA3 urine test for prostate cancer early detection

Kuan-Fu Chen¹, Tzu-Ping Lin^1,2, William J.S. Huang^1,2

¹ Department of Urology, Taipei Veterans General Hospital;

² Department of Urology, College of Medicine and Shu-Tien Urological Research Center, 

National Yang Ming Chiao Tung University

Purpose:

Numerous liquid biomarker tests have been proposed to predict Prostate Cancer, with the FDA-approved Progensa™ PCA3 urine test being one of them. PCA3, a long noncoding RNA, is considered among the most sensitive and specific biomarkers for prostate cancer. Different specimen types have been utilized for these biomarker tests, some requiring urine collection after the somewhat invasive digital rectal examination (DRE). Our study aims to identify the most suitable specimen for a novel PCA3 test in early prostate cancer detection and explores the potential to avoid invasive sample collection.

Materials and Methods:

In total, 24 men with suspected prostate cancer detected by DRE and an increased serum prostate specific antigen (ranged 4~20 ng/ml) were recruited from a tertiary medical center. Urine samples were collected before and after DRE procedure. Pre-DRE urine samples underwent further processing with exosome ribonucleic acid (RNA) purification. The PCA3 expression of these study samples (pre-DRE, post-DRE, and processed pre-DRE urine samples) were analyzed using the Simultaneous Amplification and Testing (SAT) platform. Sensitivity-specificity analyses were conducted to predict prostate cancer based on subsequent biopsy results.

Results:

Among the 24 men enrolled, 15(62.5%) were proven to have prostate adenocarcinoma on subsequent biopsy. The PCA3 test in the pre-DRE exosome RNA group had the highest sensitivity of 80.0% for a threshold of 1.35, with a specificity, positive predictive value, negative predictive value of 62.5%, 80.0%, and 62.5% respectively. The Area under the ROC Curve (AUC) was 0.742. In contrast, the sensitivity of the PCA3 test using urine cell free RNA from pre-DRE and post-DRE samples reached 71.4% and 78.6% at a cut-off value of 6.55 and 6.35 respectively, with a specificity of 37.5% and 33.3% and AUC of 0.527 and 0.480.

Conclusion:

The PCA3 test developed on the SAT platform can detect PCA3 RNA in all 3 groups of specimens. Among the 3 specimens, pre-DRE urine with exosome RNA purification offers the highest sensitivity and specificity, and holds potential for further application.