G-Protein-Coupled Receptor-Associated Sorting Protein 1 Overexpression Is Involved in the Progression of Benign Prostatic Hyperplasia, Early-Stage Prostatic Malignant Diseases, and Prostate Cancer.

Simple Summary: Prostate cancer is the second most common cancer diagnosed in men and yet is the second leading cause of cancer-related deaths worldwide. This is often due to the cancer being misdiagnosed as benign prostatic hyperplasia or missed entirely due to the limited nature of the most popular detection method, prostate-specific antigen levels. The aim of this study was to assess the potential of G-protein-coupled receptor-associated sorting protein 1 (GASP-1) as a valid prostate cancer biomarker. Prostate tissue samples from healthy, benign prostatic hyperplasia, and prostate cancer patients were subjected to anti-GASP-1 polyclonal antibodies in immunohistochemical staining and enzyme-linked immunosorbent assay analyses, showing that GASP-1 levels were significantly greater in prostate cancer patients when compared to benign prostatic hyperplasia and healthy patients. Specifically in prostate cancer patients, there was a positive correlation between GASP-1 overexpression and the severity of the prostate cancer. Background/Objectives: Prostate cancer (PCa) is a prevalent malignancy, necessitating accurate diagnostic methods to distinguish it from benign conditions such as benign prostatic hyperplasia (BPH). Current diagnostic tools, relying primarily on serum prostate-specific antigen (PSA) levels, lack specificity, leading to an over-diagnosis and unnecessary treatment of patients with benign conditions. This study explores G-protein-coupled receptor-associated sorting protein 1 (GASP-1) as a more sensitive biomarker for PCa detection. Methods: Prostate tissue microarrays of healthy, BPH, and prostate cancer patients with different Gleason scores were studied. Polyclonal antibodies targeted against GASP-1 were used for routine immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA) analyses. Results: The results indicated a 5-fold difference in serum GASP-1 levels between BPH and PCa, which was validated through GASP-1 IHC. Furthermore, a novel scoring system, the H-score, assesses GASP-1 granules' intensity and size, revealing a clear distinction between BPH and PCa. An additional analysis of GASP-1 expression between PCa cases with different Gleason scores reveals that GASP-1 overexpression correlates with PCa severity, providing insights into disease progression. Conclusions: The study supports GASP-1′s role as a promising diagnostic marker, supplementing PSA testing, and offering improved risk stratification for PCa. Additionally, an open-source software system is introduced for an efficient GASP-1 granule color analysis, enhancing diagnostic accuracy. [ABSTRACT FROM AUTHOR]