Table 2.
Summary of EV protein biomarkers identified in PCa for clinical diagnosis
| Putative PCa marker | Human sample | EV source | Markers for EV identification | EV isolation | Stage of the disease | Main result | Ref. |
|---|---|---|---|---|---|---|---|
| CK18 | PCa patients (n=6), healthy controls (n=5) | Plasma, cell line (DU145) | CD81, TSG101 | UC; Precipitation | N/A | CK18 were significantly enriched in EVs and in line with CK18 IHC in human PCa tissues | 95 |
| PSA | PCa patients (n=15), BHP patients (n=15), healthy controls (n=15) | Plasma, cell line (LNCaP) | CD81, TSG101 | UC | Prostate adenocarcinoma, total PSA was > 2.5 ng/ml |
LNCaP EVs express significant levels of PSA PCa had four-fold higher PSA-specific exosomes than BPH and healthy controls Acidic condition stimulated the release of PSA-specific exosome |
24 |
| PTEN | PCa patients (n=30), healthy controls (n=8) | Plasma, cell lines (DU145, PC-3, U87, HAOEC, HAOSMC, HPEC) | Flotilin-1 | UC | Advanced (T3/T4) tumour stage | PTEN was detected in PCa cell/plasma exosomes instead of normal cell/plasma exosomes | 96 |
| PSMA | PCa patients (n=82), BPH patients (n=28) | Plasma | CD63 | Precipitation | Low- (n = 17); intermediate- (n = 36); high-risk (n = 29) PCa according to the National Comprehensive Cancer Network risk group |
PSMA EVs concentration was higher in PCa than BPH Patients with lower PSMA EVs concentration had a larger prostate volume, lower GS and lower risk of biochemical failure |
97 |
| Survivin | PCa patients (n=39), BPH patients (n=20), healthy controls (n=16) | Plasma; serum | Lamp1 | UC; Precipitation | Plasma: ten low-grade PCa cases (GS 6); ten high-grade PCa cases (GS 9); Nineteen serum samples: N/A |
Survivin existed in plasma exosomes of normal, BPH and PCa Survivin level in PCa exosome was significantly higher than BPH and Control Survivin exosome level in relapsed chemotherapy patients was higher than controls |
98 |
| GGT | PCa patients (n=31), BPH patients (n=8) | Serum, cell lines (LNCaP, C4, C4-2, C4-2B) | CD9, PDCD6IP | UC, Size-Exclusion Chromatography, Immunoaffinity intonations | PCa patients: PSA: 4.20-28.23 ng/mL BPH patients: 4.42-25.40 ng/mL |
GGT1 was elevated in exosomes isolated from C4-2 and C4-2B cells The level of GGT-specific exosomes was significantly higher in PCa than BPH |
58 |
| P-gp | CRPC patients (6 therapy-naïve and 4 clinically docetaxel-resistant PCa patients) | Serum, cell lines (PC-3, PC3-R) | CD9 | UC | 6 therapy-naïve: PSA: 1.481-7.875 ng/mL, GS 6-8; 4 clinically docetaxel resistant PCa patients: PSA: 26.177-25313.0 ng/mL, GS 8-10 |
P-gp was higher in PC-3R exosomes than PC-3 P-gp exosome level was higher in clinically docetaxel-resistant patients than in therapy-naïve patients |
99 |
| δ-Catenin, caveolin-1, CD59 | PCa patients (n=16) PCa inactive patients (n=15) |
Urine, Cell lines (PC-3, CWR22Rv-1) | UC | PSA: 0.3-667 ng/mL, GS 6-8 | δ-Catenin, caveolin-1, CD59 were detected in cell-free urine EVs δ-Catenin had a significant increase in PCa compared to PCa inactive patients |
100 | |
| FABP5 | PCa patients (n=30), negative control group* (n=17) | Urine, cell lines (PC3, DU145) | CD9, CD63, CD81 | UC | GS6, PSA: 4.1-126 (n=6); GS8-9, PSA: 6.8-311 (n=6); low-risk PCa, GS6, PSA: 2.9-10.6 (n=5); high-risk PCa, GS7-9, PSA: 4.3-3143 (n=13) |
FABP5 was overexpressed in PCa EVs compared to negative control group FABP5 in urinary EVs was significantly associated with GS |
101 |
| TMEM256- LAMTOR1, ADIRF, VATL, Rab, PSA, FOLH1/ PMSA, TGM4, TMPRSS | PCa patients (n=17), healthy controls (n=15) | Urine | CD9, CD81, TSG101 | UC | GS6-9, PSA: 4.5-23 (n=16); 1 patient N/A due to the low exosomal protein yield and excluded from the proteomic analysis |
Combined TMEM256- LAMTOR1 augmented the sensitivity to 100% with AUC= 0.94 ADIRF, VATL and 18 different Rab proteins were enriched in PCa urinary exosomes PSA, FOLH1/PMSA, TGM4, TMPRSS were enriched in the urinary exosomes as well but with lower degree of specificity and /or sensitivity compared to TMEM256- LAMTOR1 |
102 |
| PARK7- Flotillin 2 | PCa patients (n=26), healthy controls (n=16) | Urine | N/A | UC | GS6-8, PSA: 4.4-22.6 (n=26) | Flotillin 1, Flotillin 2, Rab3B can be used to separate PCa and healthy males Flotillin 2 detected by Western blot has AUC-0.914 ELISA tests of Flotillin 2 and PARK7 can discriminate PCa from control with AUC of 0.65 and 0.71 respectively Combination of Flotillin 2 and PARK7 improved the diagnostic accuracy and robustness |
103 |
| ADSV-TGM4, CD63-GLPK5-SPHM-PSA-PAP |
PCa patients (n=53), BPH patients (n=54) | Urine | CD81, TSG101, RaB5 | UC | Low-grade PCa GS ≤ 7 (3+4) (n=22); high-grade PCa GS ≥ 7 (4+3) (n=31) |
Combination of protein panel improved the ability to distinguish benign from PCa samples ADSV-TGM4 AUC=0.65 CD63-GLPK5-SPHM-PSA-PAP AUC=0.70 |
104 |
| ITGA3, ITGB1 | Metastatic PCa patients (n=3), PCa patients (n=5), BPH patients (n=5) | Urine, cell lines (LNCaP, PC3) | PDCD6IP | UC | Metastatic PCa patients (n=3); PCa patients (n=5), | ITGA3 showed low level in LNCaP exosomes and was hardly detectable in PC3 exosomes. ITGB1 was not detectable in LNCaP exosomes and had some expression in PC3 exosomes ITGA3, ITGB1 had a higher level in metastatic patient than BHP and PCa |
105 |
Notes: *The “negative” group comprised the patients who received prostate biopsy due to elevated PSA levels and were diagnosed pathologically as negative. Abbreviations: ADIRF : adipogenesis regulatory factor; ADSV: Adseverin; AUC, Area under the curve; BPH: benign prostatic hyperplasia; PCa, prostate cancer; CD9: CD9 molecule; CD63: CD63 molecule; CD81: CD81 molecule; CK18, cytokeratin 18; CRPC, Castration-resistant prostate cancer; ELISA: enzyme-linked immunosorbent assays; EVs: Extracellular vesicles; FABP5: Fatty acid binding protein 5; GGT: Gamma-glutamyltransferase; GLPK5: Putative glycerol kinase 5; GS, Gleason score; IHC, Immunohistochemistry; ITGA3: Integrin subunit alpha 3; ITGB1: Integrin Subunit Beta 1; LAMTOR1: Late endosomal/lysosomal adaptor, MAPK and MTOR activator 1; N/A: not applicable; PARK7: Parkinsonism associated deglycase; PAP: Prostatic acid phosphatase; PDCD6IP: programmed cell death 6 interacting protein; P-gp: P-glycoprotein; PSA, Prostate specific antigen; PSMA, Prostate-specific membrane antigen; PTEN: Phosphatase and tensin homolog; RaB5: RAB5A, member RAS oncogene family; RAB3B: RAB3B, member RAS oncogene family; SPHM: N-sulphoglucosamine sulphohydrolase; TGM4: Transglutaminase-4; TMEM256: Transmembrane protein 256; TMPRSS: transmembrane protease, serine 2; TSG101: Tumour susceptibility gene 101; VATL: V-type proton ATPase 16 kDa proteolipid subunit