Multiple recognition assay reveals prostasomes as promising plasma biomarkers for prostate cancer

Abstract

Evaluation of: Tavoosidana G, Ronquist G, Darmanis S et al. Multiple recognition assay reveals prostasomes as promising plasma biomarkers for prostate cancer. Proc. Natl Acad. Sci. USA 108(21), 8809–8814 (2011).

Prostate cancer is the most prevalent cancer in men over the age of 50 years. Prostate-specific antigen is limited as both an early detection and prognostic biomarker. Prostasomes are unique microvesicles of endocytic origin with a unique lamellar membrane composed of cholesterol and phospholipids known to be capable of fusing with other cells and thus acting as messengers between cells. The evaluated article presents a new highly sensitive and specific protein-targeted assay based upon a proximity ligation assay (PLA) deemed capable of detecting prostasomes in the blood plasma of men with prostate cancer. The 4-PLA assay was used to detect circulating prostasomes in men with prostate cancer compared with age-matched controls. The median prostatsome levels in blood plasma were 2.5- to seven-fold higher compared with controls. The blood plasma prostasome levels correlated with Gleason 7 and higher disease versus Gleason 6 or lower and controls. This study describes for the first time a highly sensitive assay that depends upon simultaneous binding to as many as five different epitopes for detection and is thus a new and powerful tool for biomarker identification and validation.

Keywords::

• biomarker
• prostasomes
• prostate cancer
• proximity ligation assay
• tumor exosome

Financial & competing interests disclosure

Richard R Drake is supported by NIH grant no. R21 CA 137704. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.