Researchers at the University of Michigan Rogel Cancer Center have developed a new urine-based test that addresses a major problem in prostate cancer: how to separate the slow-growing form of the disease unlikely to cause harm from more aggressive cancer that needs immediate treatment.
The test, called MyProstateScore2.0, or MPS2, looks at 18 different genes linked to high-grade prostate cancer. In multiple tests using urine and tissue samples from men with prostate cancer, it successfully identified cancers classified as Gleason 3+4=7 or Grade Group 2 (GG2), or higher. These cancers are more likely to grow and spread compared to Gleason 6 or Grade Group 1 prostate cancers, which are unlikely to spread or cause other impact. More than one-third of prostate cancer diagnoses are this low-grade form. Gleason and Grade Group are both used to classify how aggressive prostate cancer is.
Results are published in JAMA Oncology.
To make MyProstateScore even stronger at identifying high-grade cancers, researchers used RNA sequencing of more than 58,000 genes and narrowed it to 54 candidates uniquely overexpressed specifically in higher-grade cancers. They tested the biomarkers against urine samples collected and stored at U-M through another major study, the National Cancer Institute’s Early Detection Research Network. This included about 700 patients from 2008-2020 who came for a prostate biopsy due to an elevated PSA level.
This first step narrowed the field to 18 markers that consistently correlated with higher grade disease. The test still includes the original MPS markers, plus 16 additional biomarkers to complement them.
From there, the team reached out to the larger Early Detection Research Network (EDRN), a consortium of more than 30 labs across the country that are similarly collecting samples. This ensured a diverse, national sampling. Knowing no specific details about the samples, the U-M team performed MPS2 testing on more than 800 urine samples and sent results back to collaborators at the NCI-EDRN. The NCI-EDRN team assessed MPS2 results against the patient records.
MPS2 was shown to be better at identifying GG2 or higher cancers. More importantly, it was nearly 100% correct at ruling out GG1 cancer.
Moreover, MPS2 was more effective at helping patients avoid unnecessary biopsies. While 11% of unnecessary biopsies were avoided with PSA testing alone, MPS2 testing would avoid up to 41% of unnecessary biopsies.
