Analysis of proteins identified in urine has led to the discovery of proteomic signatures for prostate cancer. These signatures have the potential to serve as highly accurate noninvasive biomarkers that can identify aggressive disease before surgery.1
Slow-growing, low-risk prostate cancers are a worldwide clinical dilemma, as they may never actually need to be treated and are at risk for overtreatment, explained Thomas Kislinger, PhD, senior scientist at the Princess Margaret Cancer Centre, University Health Network, Toronto, Canada, and principal investigator of this study.
“We believe we have found a better way that allows us to predict which patients have a slow-growing vs aggressive prostate cancer using noninvasive biomarkers. This could eventually help us personalize cancer treatment for these patients,” reported Kislinger.
Currently, prostate cancer is diagnosed via needle biopsy, but this method can miss hidden tumors and cancer that has already spread beyond the organ. “A fluid-based biomarker would be ideal … to spare patients with indolent [slow-growing] disease from unnecessary procedures, while identifying and treating those who would benefit from treatment intensification,” explained Yunee Kim, MD, lead author of the study.
For this study, urine samples with prostatic secretions were collected from 210 patients after they had undergone digital rectal examination (DRE). The study was conducted over 4 years, collecting samples from approximately 300 patients.
“We used targeted proteomics to accurately quantify hundreds of proteins in urine samples (post-DRE) to identify liquid biopsy signatures. The first round of research involved 80 patients and quantified 150 proteins that were then narrowed down to 34 for further investigation. The next round involved a second, independent cohort of 210 patients,” said Kislinger.
“Applying computational biology, we used the quantitative data from mass spectrometry to develop the fluid biomarkers for aggressive prostate cancer.”
Kislinger explained that the next steps will be further validation with urine samples from 1000 international patients to determine if the identified biomarkers have broader uses in the clinic for prostate cancer.
1. Kim Y, Jeon J, Mejia S, et al. Targeted proteomics identified liquid-biopsy signatures for extracapsular prostate cancer. Nat Commun. 2016;7:11906. doi: 10.1038/ncomms11906.