Noninvasive Urine Test Developed for Prostate Cancer

It is estimated that 191,930 men will be diagnosed with prostate cancer (PCa) in USA this year, and 33,330 of these patients will die of the disease this year. PCa is one of the second most frequently diagnosed cancer deaths among men worldwide.

Serum prostate specific antigen (PSA) levels are been used for PCa diagnosis and screening for over thirty years, and digital rectal examination (DRE) for even longer. However, PSA has modest sensitivity and specificity and does not discriminate indolent from aggressive cancers.

An international team of scientists led by the Johns Hopkins Kimmel Cancer Center (Baltimore, MD, USA) collected urine samples from 20 benign prostatic hyperplasia (BPH), 11 prostatitis (PTT), and 20 prostate cancer (PCa) patients and 20 normal healthy individuals with no history of cancer. An additional 55 urine samples (11 samples from each different Gleason score) were obtained from other patients.

The team conducted global metabolomics using ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) on a Thermo Q Exactive with Dionex UHPLC (Thermo Fisher Scientific, Waltham, MA, USA). Total RNAs from cell lines were purified using the Direct-zol RNA Miniprep kit (Zymo Research, Irvine, CA, USA) and qPCR was performed using a Power SYBR Green PCR master mix (Applied Biosystems) in the 7500 Real-Time PCR system (Applied Biosystems, Middletown, CT, USA). Additional assays were also performed.

The investigators reported that differentially expressed RNAs were identified in urine samples by deep sequencing and metabolites in urine that were measured by mass spectrometry. Messenger RNA (mRNA) and metabolite profiles were distinct in patients with benign and malignant disease. Integrated analysis of urinary gene expression and metabolite signatures unveiled an aberrant glutamate metabolism and tricarboxylic acid (TCA) cycle node in prostate cancer-derived cells. Functional validation supported a role for glutamate metabolism and glutamate oxaloacetate transaminase 1 (GOT1)-dependent redox balance in PCa, which could be exploited for novel biomarkers and therapies.

Ranjan Perera, PhD, an Associate Professor of Oncology and the study's senior author, said, “A simple and noninvasive urine test for prostate cancer would be a significant step forward in diagnosis. Tissue biopsies are invasive and notoriously difficult because they often miss cancer cells, and existing tests, such as PSA (prostate-specific antigen) elevation, are not very helpful in identifying cancer.” The study was published on February 28, 2020 in the journal Scientific Reports.

Related Links:
Johns Hopkins Kimmel Cancer Center
Thermo Fisher Scientific
Zymo Research
Applied Biosystems