The Technical University of Munich (TUM) in Germany has developed a new blood test to predict drug resistance in advanced prostate cancer patients.
Researchers designed the new test to reliably, quickly and inexpensively detect the presence of AR-V7 at an early stage, as well as to identify tumour resistance to abiraterone and enzalutamide therapy.
Commonly found in prostate cancer, AR-V7 is a receptor variant that signals cancer cells to continue dividing and spreading even in the absence of testosterone.
University Hospital TUM Klinikum rechts der Isar Urology specialist professor Dr Matthias Heck said: “If we know in advance whether or not a tumour has developed cells with this receptor, we can provide advice on an individual basis at an early stage. This can spare seriously ill patients from undergoing an ineffective therapy.”
The new test measures the amount of AR-V7 RNA molecules in the blood. Presence of high levels is linked to the greater amount of tumour cells resistant to abiraterone and enzalutamide.
As the RNA molecules are present in every tumour cell containing the resistant receptors, it is expected that the test will not encounter any undetected cells, increasing its accuracy.
The test is also considered to be highly sensitive as it requires very little amounts of RNA.
During the analysis of blood samples from 85 patients, the test was reported to have successfully detected the presence of large amounts of AR-V7 RNA in the blood of one fifth of the participants.
It was found that these patients experienced failed response to abiraterone and enzalutamide, quick return of tumours, and shorter survival times.
Image: As the test detects RNA molecules via Droplet Digital PCR, the samples are pipetted in 96-well PCR-racks. Photo: courtesy of Andreas Heddergott/TUM.