High level PSMA expression is associated with early PSA recurrence in surgically treated prostate cancer

Upregulation of SPDEF is associated with poor prognosis in prostate cancer

SAM pointed domain-containing Ets transcription factor (SPDEF), a member of the ETS transcription factor family, has been associated with prostate cancer development; however, its role in tumour development and progression is controversial. In the present study, SPDEF expression was analysed on a tissue microarray with >12,000 prostate cancer samples. SPDEF expression levels were higher in most prostate cancer samples than in normal prostate epithelium, suggesting SPDEF was upregulated in cancer. Nuclear SPDEF expression was identified in 80% of prostate cancer samples, and considered weak in 26.4%, moderate in 40.1% and strong in 13.5% of cases. SPDEF positivity was significantly associated with tumour stage, Gleason grade, lymph node metastasis and PSA recurrence (all P<0.0001). SPDEF overexpression was more common in ERG positive (94%) than in ERG negative cancer (69%; P<0.0001). Elevated SPDEF expression predicted poor prognosis independent from established prognostic parameters, including Gleason grade, pT, pN, serum PSA level and nodal status (P<0.01). In summary, SPDEF overexpression was associated with aggressive behaviour, particularly in ERG negative prostate cancer, and may have potential for clinical application.

Prognostic and diagnostic role of PSA immunohistochemistry: A tissue microarray study on 21,000 normal and cancerous tissues

To assess the prognostic and diagnostic utility of PSA immunostaining, tissue microarrays containing 17,747 prostate cancers, 3,442 other tumors from 82 different (sub) types and 608 normal tissues were analyzed at two different antibody concentrations (1:100 and 1:800). In normal tissues, PSA expression was limited to prostate epithelial cells. In prostate cancers, PSA staining was seen in 99.9–100% (1:800–1:100) primary tumors, 98.7–99.7% of advanced recurrent cancers, in 84.6–91.4% castration resistant cancers, and in 7.7–18.8% of 16 small cell carcinomas. Among extraprostatic tumors, PSA stained positive in 0–3 (1:800-1:100) of 19 osteosarcomas, 1-2 of 34 ovarian cancers, 0-2 of 35 malignant mesotheliomas, 0–1 of 21 thyroid gland carcinomas and 0–1 of 26 large cell lung cancers. Reduced staining intensity and loss of apical staining were strongly linked to unfavorable tumor phenotype and poor prognosis (p < 0.0001 each). This was all the more the case if a combined “PSA pattern score” was built from staining intensity and pattern. The prognostic impact of the “PSA pattern score” was independent of established pre- and postoperative clinico-pathological prognostic features. In conclusion, PSA immunostaining is a strong prognostic parameter in prostate cancer and has high specificity for prostate cancer at a wide range of antibody dilutions.

The Use of MRI and PET Imaging Studies for Prostate Cancer Management: Brief Update, Clinical Recommendations, and Technological Limitations

Multi-parametric magnetic resonance imaging (mpMRI) and positron emission tomography (PET) using prostate-specific membrane antigen (PSMA) targeting ligands have been adopted as a new standard of imaging modality in the management of prostate cancer (PCa). Technological advances with hybrid and advanced computer-assisted technologies such as MR/PET, MR/US, multi-parametric US, and robotic biopsy systems, have resulted in improved diagnosis and staging of patients in various stages of PCa with changes in treatment that may be considered “personalized”. Whilst newer clinical trials incorporate these novel imaging modalities into study protocols and as long-term data matures, patients should be made aware of the potential benefits and harm related to these technologies. Published literature needs to report longer-term treatment efficacy, health economic outcomes, and adverse effects. False positives and negatives of these imaging modalities have the potential to cause harm and the limitations of these technologies should be appreciated. The role of a multi-disciplinary team (MDT) and a shared-decision-making model are important to ensure that all aspects of the novel imaging modalities are considered.

Analysis of AR/ARV7 Expression in Isolated Circulating Tumor Cells of Patients with Metastatic Castration-Resistant Prostate Cancer (SAKK 08/14 IMPROVE Trial)

Despite several treatment options and an initial high response rate to androgen deprivation therapy, the majority of prostate cancers will eventually become castration-resistant in the metastatic stage (mCRPC). Androgen receptor splice variant 7 (ARV7) is one of the best-characterized androgen receptor (AR) variants whose expression in circulating tumor cells (CTCs) has been associated with enzalutamide resistance. ARV7 expression analysis before and during enzalutamide treatment could identify patients requiring alternative systemic therapies. However, a robust test for the assessment of the ARV7 status in patient samples is still missing. Here, we implemented an RT-qPCR-based assay for detection of AR full length (ARFL)/ARV7 expression in CTCs for clinical use. Additionally, as a proof-of-principle, we validated a cohort of 95 mCRPC patients initiating first line treatment with enzalutamide or enzalutamide/metformin within a clinical trial. A total of 95 mCRPC patients were analyzed at baseline of whom 27.3% (26/95) had ARFL+ARV7+, 23.1% (22/95) had ARFL+ARV7−, 23.1% (22/95) had ARFL−ARV7−, and 1.1% (1/95) had ARFL−ARV7+ CTCs. In 11.6% (11/95), no CTCs could be isolated. A total of 25/95 patients had another CTC analysis at progressive disease, of whom 48% (12/25) were ARV7+. Of those, 50% (6/12) were ARV7− and 50% (6/12) were ARV7+ at baseline. Our results show that mRNA analysis of isolated CTCs in mCRPC is feasible and allows for longitudinal endocrine agent response monitoring and hence could contribute to treatment optimization in mCRPC.

PSMA uptake on [68Ga]-PSMA-11-PET/CT positively corrects with prostate cancer aggressiveness

BACKGROUND

Conflict results has been revealed on the relationship between PSMA uptake values (SUVs) on PSMA PET/CT and prostate cancer aggressiveness. This study is to validate the relationship between SUVs with prostate cancer (PCa) aggressiveness and its role in evaluation of clinically significant PCa (csPCa) and risk stratification.

METHODS

We retrospectively enrolled 51 patients who underwent [68Ga]-PSMA PET/CT (PET/CT) before radical prostatectomy (RP). PET/CT results were corrected with whole mount histology. The relationship between SUVs and aggressiveness related indictors including Gleason score, T stage, initial PSA and tumor size were analyzed. The cutoff value for detection of overall PCa, csPCa and intermediate/high-risk PCa were calculated by receiver operating characteristics (ROC) analysis.

RESULTS

Both SUVmax and SUVmean positively correlated with Gleason score (SUVmax Spearman r=0.546 p<0.01, SUVmean Spearman r=0.359 p<0.01), PSA level (SUVmax Spearman r=0.568 p<0.01, SUVmean Spearman r=0.529 p<0.01) and tumor volume (SUVmax Spearman r=0.635 p<0.01, SUVmean Spearman r=0.590 p<0.01). Tumors with T3 stage had significant higher SUV uptake than T2 (SUVmax 17.49 ± 10.50 vs 9.90 ± 8.7, p<0.01 and SUVmean 17.49 ± 10.50 vs 9.90 ± 8.7, p<0.01). ROC analysis showed cutoff of SUVmax (3.8) and SUVmean (2.8) for overall PCa detection. ROC analysis showed that csPCa and intermediate/high risk PCa had the same cutoff on both SUVmax (8.4) and SUVmean (6.8).

CONCLUSIONS

PSMA uptake on PSMA PET/CT positively correlated with Gleason score, T stage, initial PSA and tumor volume. Both SUVmax and SUVmean can be applied as parameters for csPCa detection and risk classification.

68Ga-PSMA PET/CT: Does it predict adverse pathology findings at radical prostatectomy?

INTRODUCTION

Data on the accuracy of 68Ga-PSMA positron emission tomography/computed tomography (PET/CT) in patients with intermediate/high-risk prostate cancer are being accumulated. Its role in assessing the extent of local disease has not been fully elaborated.

AIM

To determine the performance characteristics of 68Ga-PSMA PET/CT in identifying local disease extension in patients with intermediate/high risk prostate cancer.

METHODS

68Ga-PSMA PET/CT studies of 61 consecutive patients with intermediate/high-risk prostate cancer who underwent radical prostatectomy were reviewed by nuclear medicine specialists. Tumor location, extraprostatic extension (EPE), seminal vesicle invasion (SVI), and lymph nodes involvement (LNI) were compared to pathological findings. The incremental value of 68Ga-PSMA PET/CT to established nomograms was determined.

RESULTS

Two patients without pathologic uptake of 68Ga-PSMA were excluded. Seventeen patients were diagnosed with EPE (29%), 12(20%) had SVI and 3(5%) LNI. The concordance between tumor location and 68Ga-PSMA PET/CT findings was 48%, and EPE was not indicated by PET in any of the patients. The sensitivity, specificity, positive, and negative predictive value for SVI were 58%, 96%, 78%, 90%, respectively (area under the receiver operating characteristic curve = 0.77) and for LNI 67%, 98%, 67%, 98%, respectively (area under the receiver operating characteristic curve = 0.82). Incorporating imaging findings into the MSKCC-SVI nomogram enhanced the diagnostic accuracy from 0.84 to 0.95 (Integrated Discrimination Increment 0.24, P = 0.004).

CONCLUSION

In patients with intermediate/high-risk prostate cancer, 68Ga-PSMA PET/CT provides information regarding intraprostatic tumor location, SVI and LNI but has no role in assessment for EPE. This information might be useful for pretreatment counseling, decision-making and possibly preoperative planning.

Development and characterization of a theranostic multimodal anti-PSMA targeting agent for imaging, surgical guidance, and targeted photodynamic therapy of PSMA-expressing tumors

Rationale: Prostate cancer (PCa) recurrences after surgery frequently occur. To improve the outcome after surgical resection of the tumor, the theranostic multimodal anti-PSMA targeting agent ¹¹¹In-DTPA-D2B-IRDye700DX was developed and characterized for both pre- and intra-operative tumor localization and eradication of (residual) tumor tissue by PSMA-targeted photodynamic therapy (tPDT), which is a highly selective cancer treatment based on targeting molecules conjugated to photosensitizers that can induce cell destruction upon exposure to near-infrared (NIR) light.

Methods: The anti-PSMA monoclonal antibody D2B was conjugated with IRDye700DX and DTPA and subsequently radiolabeled with ¹¹¹In. To determine the optimal dose and time point for tPDT, BALB/c nude mice with PSMA-expressing (PSMA⁺) s.c. LS174T-PSMA xenografts received the conjugate (24-240 µg/mouse) intravenously (8 MBq/mouse) followed by µSPECT/CT, near-infrared fluorescence imaging, and ex vivo biodistribution at 24, 48, 72 and 168 h p.i. Tumor growth of LS174T-PSMA xenografts and overall survival of mice treated with 1-3 times of NIR light irradiation (50, 100, 150 J/cm²) 24 h after injection of 80 µg of DTPA-D2B-IRDye700DX was compared to control conditions.

Results: Highest specific tumor uptake was observed at conjugate doses of 80 µg/mouse. Biodistribution revealed no significant difference in tumor uptake in mice at 24, 48, 72 and 168 h p.i. PSMA⁺ tumors were clearly visualized with both µSPECT/CT and NIR fluorescence imaging. Overall survival in mice treated with 80 µg of DTPA-D2B-IRDye700DX and 1x 150 J/cm² of NIR light at 24 h p.i. was significantly improved compared to the control group receiving neither conjugate nor NIR light (73 days vs. 16 days, respectively, p=0.0453). Treatment with 3x 150 J/cm² resulted in significantly prolonged survival compared to treatment with 3x 100 J/cm² (p = 0.0067) and 3x 50 J/cm² (p = 0.0338).

Principal conclusions:¹¹¹In-DTPA-D2B-IRDye700DX can be used for pre- and intra-operative detection of PSMA⁺ tumors with radionuclide and NIR fluorescence imaging and PSMA-targeted PDT. PSMA-tPDT using this multimodal agent resulted in significant prolongation of survival and shows great potential for treatment of (metastasized) prostate cancer.

Phase 1 study of PSMA ADC, an antibody-drug conjugate targeting prostate-specific membrane antigen, in chemotherapy-refractory prostate cancer

BACKGROUND

Prostate-specific membrane antigen (PSMA) is a well-characterized target that is overexpressed selectively on prostate cancer cells. PSMA antibody-drug conjugate (ADC) is a fully human IgG1 monoclonal antibody conjugated to the microtubule disrupting agent monomethyl auristatin E (MMAE), which is designed to specifically bind PSMA-positive cells, internalize, and then release its cytotoxic payload into the cells. PSMA ADC has demonstrated potent and selective antitumor activity in preclinical models of advanced prostate cancer. A Phase 1 study was conducted to assess the safety, pharmacokinetics, and preliminary antitumor effects of PSMA ADC in subjects with treatment-refractory prostate cancer.

METHODS

In this first-in-man dose-escalation study, PSMA ADC was administered by intravenous infusion every three weeks to subjects with progressive metastatic castration-resistant prostate cancer (mCRPC) who were previously treated with docetaxel chemotherapy. The primary endpoint was to establish a maximum tolerated dose (MTD). The study also examined the pharmacokinetics of the study drug, total antibody, and free MMAE. Antitumor effects were assessed by measuring changes in serum prostate-specific antigen (PSA), circulating tumor cells (CTCs), and radiologic imaging.

RESULTS

Fifty-two subjects were administered doses ranging from 0.4 to 2.8 mg/kg. Subjects had a median of two prior chemotherapy regimens and prior treatment with abiraterone and/or enzalutamide. Neutropenia and peripheral neuropathy were identified as important first-cycle and late dose-limiting toxicities, respectively. The dose of 2.5 mg/kg was determined to be the MTD. Pharmacokinetics were approximately dose-proportional with minimal drug accumulation. Reductions in PSA and CTCs in subjects treated with doses of ≥1.8 mg/kg were durable and often concurrent.

CONCLUSIONS

In an extensively pretreated mCRPC population, PSMA ADC demonstrated acceptable toxicity. Antitumor activity was observed over dose ranges up to and including 2.5 mg/kg. The observed anti-tumor activity supported further evaluation of this novel agent for the treatment of advanced metastatic prostate cancer.

Prognostic Significance of Serum PSA Level and Telomerase, VEGF and GLUT-1 Protein Expression for the Biochemical Recurrence in Prostate Cancer Patients after Radical Prostatectomy

The aim of the study was to evaluate prognosis for biochemical recurrence (BR) by analysing the pathological and biological characteristics of prostate cancer (PCa) after radical prostatectomy (RP). There were 130 men with clinically localized PCa in whom pretreatment serum PSA level and Ki-67, prostate specific membrane antigen (PSMA), glucose transporter-1 (GLUT-1), vascular endothelial growth factor (VEGF), microvessel density (MVD) and human telomerase reverse transcriptase (hTERT) proteins expression, based on number of immunohistochemically positive cells (labelling index), were retrospectively studied. In order to assess the prognostic significance of analysed variables in univariate and multivariate Cox analysis, patients were dichotomized based on cut-off points chosen by receiver operating characteristic (ROC) curves. There were 83 males (63.8%) at pT stage 1–2 and 47 (36.1%) at pT stage 3–4, respectively, with median (range) age of 62.8 years (49–77), and median follow-up of 78.5 months (12–148). In 42 (32.3%) men BR was found. In univariate analysis, tumour biological features: PSA ≤ 8 ng/mL (p = 0.006), Ki-67LI ≤ 12.7% (p = 0.015), VEGFLI>11.0% (p = 0.030), and hTERTLI>6.7% (p = 0.016), but not clinicopathological parameters, appeared to be positive prognosticators for BRFS. In the Cox analysis, Ki-67 lost its significance, and clinicopathological parameters appeared to be nonsignificant. The independent negative prognostic factors for BRFS were: PSA > 8.0 ng/mL, (Hazard ratio = 2.75, p = 0.003), GLUT-1 > 19.1% (HR = 2.1, p = 0.032), VEGF≤11.0% (HR = 1, p = 0.024) and hTERT≤6.7% (HR = 1, p = 0.017). High PSA level, and GLUT-1 expression and lower VEGF and nuclear hTERT expression may indicate the great role of hypoxia in BR induction in PCa.

Diagnostic Performance of 68Gallium Labelled Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography and Magnetic Resonance Imaging for Staging the Prostate Cancer with Intermediate or High Risk Prior to Radical Prostatectomy: A Systematic Review and Meta-analysis

Purpose

To compare the diagnostic efficiency of ⁶⁸Gallium labelled prostate-specific membrane antigen positron emission tomography (⁶⁸Ga-PSMA PET) and magnetic resonance imaging (MRI) for staging the lymph node metastases (LNMs) in the prostate cancer.

Materials and Methods

A broad search of scientific databases including PubMed, EMBASE, Web of Science, Cochrane Database, and Chinese Biomedicine Literature Database (updated prior to November 1st, 2018) was conducted systematically by two reviewers. In this paper, we evaluated the methodological quality of each included article independently and performed a systematic review and meta-analysis to reveal the summary of the diagnostic performance of ⁶⁸Ga-PSMA PET and MRI in properly identifying LNMs of intermediate- and/or high-risk prostate cancer.

Results

Thirteen eligible articles comprising 1,597 patients were included. For LNMs detection, the pooled sensitivity and specificity of ⁶⁸Ga-PSMA PET were 0.65 (95% confidence interval [CI]: 0.49–0.79) and 0.94 (95% CI: 0.88–0.97), respectively, while the corresponding values of MRI were 0.41 (95% CI: 0.26–0.57) and 0.92 (95% CI: 0.86–0.95). The area under the symmetric receiver-operating characteristic (SROC) curve for ⁶⁸Ga-PSMA PET and MRI were 0.92 and 0.83, respectively.

Conclusions

In intermediate- or high-risk pre-treatment prostate cancer, ⁶⁸Ga-PSMA PET had a higher sensitivity and a slightly different specificity in probing the LNMs when comparing with MRI. Moreover, the area under the SROC curve indicated that ⁶⁸Ga-PSMA PET was a more effective weapon for predicting the LNMs prior to radical surgery.

The proteasome inhibitor, bortezomib, induces prostate cancer cell death by suppressing the expression of prostate-specific membrane antigen, as well as androgen receptor

The progression of primary prostate cancer (PC) is dependent on the androgen receptor (AR) and prostate‑specific membrane antigen (PSMA). Furthermore, the growth of PC cells is terminated with the downregulation of both AR and PSMA. In our preliminary experiments, it was also found that bortezomib (BZ; PS‑341) that inhibits 26S proteasome activity, acts as a downregulator of both PSMA and AR. In addition to evaluating the effects of BZ on protein expression, the present study evaluated and compared the anticancer effects of BZ on the growth of cells treated with BZ, docetaxel (DOC), or a combination of both. Western blot analysis was used to examine the expression levels of AR and PSMA. The knockdown effect of small interfering RNA (siRNA) and the drugs on the expression of either AR or PSMA was also evaluated. An MTT assay was performed in order to evaluate the inhibitory effects of the drugs on PC cells. The cell cycles were analyzed, and apoptotic cells were detected. The downregulation of AR and PSMA was observed using siRNA specific to AR or PSMA, and the inhibition of PSMA, as well as that of AR severely suppressed the growth of PC cells. The inhibitory effect of BZ alone on PSMA expression was similar to that of both AR‑ and PSMA‑specific siRNA, and this drug also induced the downregulation of AR and PSMA in PC cells. This phenomenon was confirmed even in cells transfected to overexpress PSMA. The apoptosis‑promoting effect of BZ on the cells was similar to that observed with BZ plus DOC, and more potent than that of DOC alone. BZ had the same inhibitory effect on the expression of AR and PSMA as did siRNA specific to AR or PSMA. On the whole, the findings of this study indicate that BZ may prove to be a promising chemotherapeutic agent and may be used as a molecularly targeted drug in the treatment of PC.

[177Lu]Lu-PSMA-617 Salivary Gland Uptake Characterized by Quantitative In Vitro Autoradiography

Irradiation of salivary glands remains the main dose-limiting side effect of therapeutic PSMA-inhibitors, especially when using alpha emitters. Thus, further advances in radiopharmaceutical design and therapy strategies are needed to reduce salivary gland uptake, thereby allowing the administration of higher doses and potentially resulting in improved response rates and better tumor control. As the uptake mechanism remains unknown, this work investigates the salivary gland uptake of [¹⁷⁷Lu]Lu-PSMA-617 by autoradiography studies on pig salivary gland tissue and on PSMA-overexpressing LNCaP cell membrane pellets. Displacement studies were performed with non-labeled PSMA-617 and 2-PMPA, respectively. The uptake of [¹⁷⁷Lu]Lu-PSMA-617 in glandular areas was determined to be partly PSMA-specific, with a high non-specific uptake fraction. The study emphasizes that [¹⁷⁷Lu]Lu-PSMA-617 accumulation in pig salivary glands can be attributed to a combination of both specific and non-specific uptake mechanisms. The observation is of high impact for future design of novel radiopharmaceuticals addressing the dose-limiting salivary gland irradiation of current alpha endoradiotherapy in prostate cancer.

First-in-human study of 177Lu-EB-PSMA-617 in patients with metastatic castration-resistant prostate cancer

PURPOSE

This translational study is designed to assess the safety, dosimetry and therapeutic response to a single, low-dose of 177Lu-EB-PSMA-617 in comparison to 177Lu-PSMA-617 in patients with mCRPC.

METHODS

Following institutional review board approval and informed consent, nine patients with mCRPC were recruited. Four patients accepted intravenous injection of 0.80-1.1 GBq (21.5-30 mCi) of 177Lu-EB-PSMA-617, then underwent serial whole-body planar and SPECT/CT imaging at 2, 24, 72, 120 and 168 h. The other five patients accepted intravenous injection of 1.30-1.42 GBq (35-38.4 mCi) 177Lu-PSMA-617, then underwent the same imaging procedures at 0.5, 2, 24, 48, and 72 h. All patients were evaluated by 68Ga-PSMA-617 PET/CT before and one month after the treatment. Dosimetry evaluation was compared in both patient groups.

RESULTS

When the bone metastasis tumors with comparable baseline SUVmax in the range of 10.0-15.0 were selected from the two groups for comparison, the accumulated radioactivity of 177Lu-EB-PSMA-617 was about 3.02-fold higher than that of 177Lu-PSMA-617. Imaging dose of 177Lu-EB-PSMA-617 treatment showed significant decrease of 68Ga-PSMA-617 uptake within a month, which was not observed in patients imaged with 177Lu-PSMA-617 (SUV change: -32.43 ± 0.14% vs. 0.21 ± 0.37%; P = 0.002). 177Lu-EB-PSMA-617 also had higher absorbed doses in the red bone marrow and kidneys than 177Lu-PSMA-617 (0.0547 ± 0.0062 vs. 0.0084 ± 0.0057 mSv/MBq for red bone marrow, P < 0.01; 2.39 ± 0.69 vs. 0.39 ± 0.06 mSv/MBq for kidneys, P < 0.01).

CONCLUSION

This first-in-human study demonstrated that 177Lu-EB-PSMA-617 had higher accumulation in mCRPC and that low imaging dose appears to be effective in treating tumors with high 68Ga-PSMA-617 uptakes. Elevated uptakes of 177Lu-EB-PSMA-617 in kidneys and red bone marrow were well tolerated at the administered low dose. Further investigations with increased dose and frequency of administration are warranted.

Loss of PSP94 expression is associated with early PSA recurrence and deteriorates outcome of PTEN deleted prostate cancers

Objective

Prostate secretory protein of 94 amino acids (PSP94) is a target gene of the EZH2 transcriptional repressor and is often downregulated in prostate cancer; however, its prognostic value is disputed.

Methods

Immunohistochemical analysis of a tissue microarray of 12, 432 prostate cancer specimens was performed to evaluate PSP94 expression. Correlation of PSP94 expression with tumor phenotype, patient prognosis, TMPRSS2:ERG fusion status, EZH2 expression and PTEN deletion was studied.

Results

PSP94 expression was increased in benign prostatic hyperplasia; however, it was downregulated in 48% and negative in 42% of the 9, 881 interpretable prostate cancer specimens. The loss of PSP94 expression was inversely correlated to EZH2 expression (P < 0.0001) and largely unrelated to the ERG status, but strongly correlated with high Gleason grade, advanced tumor stage, and nodal metastasis ( P <0.0001 each). The fraction of PSP94-negative cancer specimens increased from 40% in pT2 to 52% in pT3b-pT4 ( P < 0.0001) and from 40% in Gleason 3+3 = 6 to 46% in Gleason 4+3 = 7 and 60% in Gleason ≥4+4 = 8 ( P < 0.0001). Loss of PSP94 was linked to early prostate-specific antigen recurrence, but with little absolute effect ( P < 0.0001). However, it provided additional prognostic impact in cancer specimens with PTEN deletion. Loss of PSP94 deteriorated prognosis of cancer patients with PTEN deletion by more than 10% (P < 0.0001). The combination of PTEN deletion and PSP94 loss provided independent prognostic information that was observed in several subgroups defined by classical and quantitative Gleason grade.

Conclusions

The results of our study suggest that combined PSP94/PTEN analysis can be potentially used in the clinical prognosis of prostate cancer.

Expression of Prostate-Specific Membrane Antigen (PSMA) on Biopsies Is an Independent Risk Stratifier of Prostate Cancer Patients at Time of Initial Diagnosis

Background: Stratifying prostate cancer (PCa) patients into risk groups at time of initial diagnosis enabling a risk-adapted disease management is still a major clinical challenge. Existing studies evaluating the prognostic potential of PSMA (prostate-specific membrane antigen) for PCa were performed on radical prostatectomy specimens (RPE), i.e., decision making for disease management was already completed at time of sample analysis. Aim of our study was to assess the prognostic value of PSMA expression for PCa patients on biopsies at time of initial diagnosis. Methods: PSMA expression was assessed by immunohistochemistry on 294 prostate biopsies with corresponding RPE, 621 primary tumor foci from 242 RPE, 43 locally advanced or recurrent tumors, 34 lymph node metastases, 78 distant metastases and 52 benign prostatic samples. PSMA expression was correlated with clinico-pathologic features. Primary endpoint was recurrence free survival. Other clinicopathologic features included WHO/ISUP grade groups, PSA serum level, TNM-stage, and R-status. Chi-square test, ANOVA-analyses, Cox-regression, and log-rank tests were performed for statistical analyses. Results: High PSMA expression on both biopsy and RPE significantly associates with a higher risk of disease recurrence following curative surgery. The 5-year-recurrence free survival rates were 88.2, 74.2, 67.7 and 26.8% for patients exhibiting no, low, medium, or high PSMA expression on biopsy, respectively. High PSMA expression on biopsy was significant in multivariate analysis predicting a 4-fold increased risk of disease recurrence independently from established prognostic markers. PSMA significantly increases during PCa progression. Conclusion: PSMA is an independent prognostic marker on biopsies at time of initial diagnosis and can predict disease recurrence following curative therapy for PCa. Our study proposes the application of the routinely used IHC marker PSMA for outcome prediction and decision making in risk-adapted PCa management on biopsies at time of initial diagnosis.

Efficacy of early imaging with 68Ga-PSMA-I&T in the discrimination of pelvic lesions in prostate cancer patients

OBJECTIVE

⁶⁸Ga-PSMA-uptake shows accumulation in the malignant lesions of prostate cancer patients as early as 5min p.i. Studies indicate the value of adding an early image of the pelvis to the imaging protocol of ⁶⁸Ga-PSMA-11 PET/CT scan showed contradictory results. In this study we planned to assess the significance of an additional early imaging in ⁶⁸Ga-PSMA-I&T PET/CT imaging in prostate cancer patients.

MATERIALS AND METHODS

A total of 35 prostate cancer patients referred to ⁶⁸Ga-PSMA-I&T PET/CT imaging for restaging of the disease due to suspicion of relapse after definitive therapy were enrolled. First an early static pelvic image was obtained at a maximum of 300s following injection of the radiotracer. Sixty minutes postinjection a whole-body PET/CT scan was conducted with an emission time of 3min per bed position. The lesions which were categorized as local recurrence, bone lesion and lymph node metástasis in the early images, were compared with the late images in terms of number of lesions detected and SUVmax values.

RESULTS

⁶⁸Ga-PSMA-I&T PET/CT was positive in 23 of 35 patients (65.7%). A pathological uptake was observed in the prostatic bed site, in the pelvic lymph nodes, and in the bones in 17 patients (48.5%), 12 patients (34.2%), and 13 patients (37.1%), respectively. In one patient, focal pathological increased uptake in the prostatic bed with a SUVmax value of 5.8 was detected but this lesion disappeared in the late images. The average SUVmax values of the lesions in the prostatic bed were 13.7±12.1 versus 26.3±23.8 in the 5min and 60min studies respectively (p<0.001). In one patient, the pathological uptake in the lymph node in the early study cleared in the late study, whereas in another accumulation of activity was detected in a pelvic lymph node in the late study, while there was no lymph node detected in the early study. The average SUVmax values of the lymph nodes were 12.1±8.8 versus 26.3±22.6 in the 5min and 60min studies respectively (p<0.001). The average SUVmax values of the bone lesions were 11.4±6.9 versus 15±10.7 in the 5min and 60min studies respectively.

CONCLUSION

Our study is the first in the literature to evaluate the impact of adding an early static pelvic image to the ⁶⁸Ga-PSMA-I&T scan, in the detection rate of the lesions. Although there was no marked discordance between the 2sets of images, the addition of an early image to the imaging protocol of ⁶⁸Ga-PSMA-I&T scan would increase the efficacy of detection of malignant lesions in the pelvis, which might show rapid clearance and has the risk of being masked by the urinary system activity.

Dendritic cells pulsed with prostate-specific membrane antigen in metastatic castration-resistant prostate cancer patients: a systematic review and meta-analysis

BACKGROUND

Dendritic cells (DCs) are used in many malignancies as vaccines to induce immunity against specific cancer antigens. The role of DCs in metastatic castration-resistant prostate cancer (mCRPC) is not determined. In this study, the proportion of mCRPC patients with clinically significant response to targeted therapy by DCs pulsed with prostate-specific membrane antigen was evaluated, and the possible adverse effects of this modality were investigated.

METHODS

Major databases were searched up to Feb 2017, to identify studies in which the antitumor efficacy of DCs pulsed with the extracellular portion of PSMA was studied for the treatment of mCRPC. Data were collected by two reviewers and analyzed using Comprehensive Meta-Analysis software, version 2.0.

FINDINGS

Our study consisted of 6 nonrandomized prospective (cohort) trials, overall reporting on 153 mCRPC patients. The event rate that is the representative of fraction of patients showing antitumor response was 0.43 (95% confidence interval = 0.355-0.512; P = 0.097). No significant between-study heterogeneity or inconsistency was detected (I2 = 5.47; Q = 5; P = 0.382). Our study failed to demonstrate a significant therapeutic efficacy for DCs in mCRPC. However, no significant adverse effects were seen.

ExoAPP: Exosome-Oriented, Aptamer Nanoprobe-Enabled Surface Proteins Profiling and Detection

Tumor exosomes that inherit molecular markers from their parent cells are emerging as cellular "surrogates" in cancer diagnostics. Molecular profiling and detection of exosomes offer a noninvasive access to the state of cancer progression, yet are still technically challenging. Here we report an exosome-oriented, aptamer nanoprobe-based profiling (ExoAPP) assay to phenotype surface proteins and quantify cancerous exosomes in a facile mix-and-detect format. Our ExoAPP interfaces graphene oxide (GO) with target-responsive aptamers to profile exosomal markers across five cell types by complementing with enzyme-assisted exosome recycling, revealing a heterogeneous pattern.This assay achieves a detection limit down to 1.6 × 10⁵ particles/mL, lowered by several orders of magnitude over other homogeneous protocols. Such a sensitive ExoAPP assay allows for monitoring epithelial-mesenchymal transition through heterogeneous exosomes without involving cellular internalization that often occurs in GO-based cargo delivery. Using ExoAPP to analyze blood samples from prostate cancer patients, we find that target exosome can be identified by surface PSMA, suggesting their potential in clinical diagnosis.

Meeting report from the Prostate Cancer Foundation PSMA-directed radionuclide scientific working group

INTRODUCTION

The Prostate Cancer Foundation (PCF) convened a PSMA-Directed Radionuclide Scientific Working Group on November 14, 2017, at Weill Cornell Medicine, New York, NY.

METHODS

The meeting was attended by 35 global investigators with expertise in prostate cancer biology, radionuclide therapy, molecular imaging, prostate-specific membrane antigen (PSMA)-targeted agents, drug development, and prostate cancer clinical trials. The goal of this meeting was to discuss the potential for using PSMA-targeted radionuclide agents for the treatment of advanced prostate cancer and to define the studies and clinical trials necessary for validating and optimizing the use of these agents.

RESULTS

Several major topic areas were discussed including the overview of PSMA biology, lessons and applications of PSMA-targeted PET imaging, the nuances of designing PSMA-targeted radionuclide agents, clinical experiences with PSMA-targeted radionuclides, PCF-funded projects to accelerate PSMA-targeted radionuclide therapy, and barriers to the use of radionuclide treatments in widespread clinical practice.

DISCUSSION

This article reviews the major topics discussed at the meeting with the goal of promoting research that will validate and optimize the use of PSMA-targeted radionuclide therapies for the treatment of advanced prostate cancer.

The efficiency of 18F labelling of a prostate specific membrane antigen ligand via strain-promoted azide-alkyne reaction: reaction speed versus hydrophilicity

Here we report the 18F labeling of a prostate specific membrane antigen (PSMA) ligand via a strain promoted oxa-dibenzocyclooctyne (ODIBO)- or bicyclo[6.1.0]nonyne (BCN)-azide reaction. Although ODIBO reacts with azide 20 fold faster than BCN, in vivo PET imaging suggests that 18F-BCN-azide-PSMA demonstrated much higher tumor uptake and a much higher tumor to background contrast.

Oligorecurrent prostate cancer limited to lymph nodes: getting our ducks in a row : Nodal oligorecurrent prostate cancer

PURPOSE

Oligorecurrent prostate cancer with exclusive nodal involvement represents a common state of disease, amenable to local therapy. New radio-labeled tracers have enriched the possibility of cancer detection and treatment. In this review, we aim to illustrate the main nuclear medicine diagnostic options and the role of radiotherapy in this setting of patients.

METHODS

We performed a PubMed search referring to the PRISMA guidelines to analyze the performance of PSMA- and choline-PET in detecting oligorecurrence limited to lymph nodes, and to review the main studies supporting either ablative stereotactic body radiotherapy or regional lymph node irradiation in this clinical setting.

RESULTS

PSMA-PET has shown higher efficacy in the diagnosis of nodal lesions if compared with choline-PET. More specifically, for PSA ≤ 2 ng/ml, the median detection rate of choline-PET ranges from 19.5 to 44.5%, whereas PSMA ranges from 51.5 to 74%. SBRT achieves high local control rates positively affecting progression-free survival (PFS), with androgen deprivation therapy (ADT)-free survival ranging from 25 to 44 months and with low toxicity rates (0-15%). Prophylactic nodal irradiation shows 3-year PFS rates ranging from 62 to 75%, but with a potential higher risk of toxicity. However, the chosen treatment option needs to be tailored on the single patient.

CONCLUSIONS

Newer PET/CT radio-labeled tracers have increased disease detection in oligorecurrent prostate cancer patients. Growing evidence of their impact on metastasis-directed therapy encourages the use of the most advanced radiotherapy techniques in the clinical management of such patients.

External radiation exposure, excretion, and effective half-life in 177Lu-PSMA-targeted therapies

Background

Prostate-specific membrane antigen (PSMA)-targeted therapy with ¹⁷⁷Lu-PSMA-617 is a therapeutic option for patients with metastatic castration-resistant prostate cancer (mCRPC). To optimize the therapy procedure, it is necessary to determine relevant parameters to define radiation protection and safety necessities. Therefore, this study aimed at estimating the ambient radiation exposure received by the patient. Moreover, the excreted activity was quantified.

Results

In total, 50 patients with mCRPC and treated with ¹⁷⁷Lu-PSMA-617 (mean administered activity 6.3 ± 0.5 GBq) were retrospectively included in a bi-centric study. Whole-body dose rates were measured at a distance of 2 m at various time points after application of ¹⁷⁷Lu-PSMA-617, and effective half-lives for different time points were calculated and compared. Radiation exposure to the public was approximated using the dose integral. For the estimation of the excreted activity, whole body measurements of 25 patients were performed at 7 time points.

Unbound ¹⁷⁷Lu-PSMA-617 was rapidly cleared from the body. After 4 h, approximately 50% and, after 12 h, approximately 70% of the administered activity were excreted, primarily via urine. The mean dose rates were the following: 3.6 ± 0.7 μSv/h at 2 h p. i., 1.6 ± 0.6 μSv/h at 24 h, 1.1 ± 0.5 μSv/h at 48 h, and 0.7 ± 0.4 μSv/h at 72 h. The mean effective half-life of the cohort was 40.5 ± 9.6 h (min 21.7 h; max 85.7 h). The maximum dose to individual members of the public per treatment cycle was ~ 250 ± 55 μSv when the patient was discharged from the clinic after 48 h and ~ 190 ± 36 μSv when the patient was discharged after 72 h.

Conclusions

In terms of the radiation exposure to the public, ¹⁷⁷Lu-PSMA is a safe option of radionuclide therapy. As usually four (sometimes more) cycles of the therapy are performed, it must be conducted in a way that ensures that applicable legal requirements can be followed. In other words, the radiation exposure to the public and the concentration of activity in wastewater must be sub-marginal. Therefore, in certain countries, hospitalization of these patients is mandatory.

The Utility of PET/CT in the Planning of External Radiation Therapy for Prostate Cancer

Radiotherapy and radical prostatectomy are the definitive treatment options for patients with localized prostate cancer. A rising level of prostate-specific antigen after radical prostatectomy indicates prostate cancer recurrence, and these patients may still be cured with salvage radiotherapy. To maximize chance for cure, the irradiated volumes should completely encompass the extent of disease. Therefore, accurate estimation of the location of disease is critical for radiotherapy planning in both the definitive and the salvage settings. Current first-line imaging for prostate cancer has limited sensitivity for detection of disease both at initial staging and at biochemical recurrence. Integration of PET into routine evaluation of prostate cancer patients may improve both staging accuracy and radiotherapy planning. 18F-FDG PET/CT is now routinely used in radiation planning for several cancer types. However, 18F-FDG PET/CT has low sensitivity for prostate cancer. Additional PET probes evaluated in prostate cancer include 18F-sodium fluoride, 11C-acetate, 11C- or 18F-choline, 18F-fluciclovine, and 68Ga- or 18F-labeled ligands that bind prostate-specific membrane antigen (PSMA). PSMA ligands appear to be the most sensitive and specific but have not yet received Food and Drug Administration New Drug Application approval for use in the United States. Retrospective and prospective investigations suggest a potential major impact of PET/CT on prostate radiation treatment planning. Prospective trials randomizing patients to routine radiotherapy planning versus PET/CT-aided planning may show meaningful clinical outcomes. Prospective clinical trials evaluating the addition of 18F-fluciclovine PET/CT for planning of salvage radiotherapy with clinical endpoints are under way. Prospective trials evaluating the clinical impact of PSMA PET/CT on prostate radiation planning are indicated.

Family with sequence similarity 13C (FAM13C) overexpression is an independent prognostic marker in prostate cancer

FAM13C, a gene with unknown function is included in several mRNA signatures for prostate cancer aggressiveness. To understand the impact of FAM13C on prognosis and its relationship to molecularly defined subsets, we analyzed FAM13C expression by immunohistochemistry on a tissue microarray containing 12,400 prostate cancer specimens. Results were compared to phenotype, ERG status, genomic deletions of 3p, 5q, 6q and PTEN, and biochemical recurrence. FAM13C was detectable in cell nuclei of cancerous and non-neoplastic prostate cells. 67.5% of 9,633 interpretable cancers showed FAM13C expression: strong in 28.3%, moderate in 24.6% and weak in 14.6%. Strong FAM13C expression was linked to advanced pT stage, high Gleason grade, positive lymph node status, and early biochemical recurrence (p < 0.0001 each). FAM13C expression was associated with TMPRSS2:ERG fusions. It was present in 85% of ERG positive but in only 54% of ERG negative cancers (p < 0.0001), and in 91.1% of PTEN deleted but in only 69.2% of PTEN non-deleted cancers (p < 0.0001). The prognostic role of FAM13C expression was independent of classical and quantitative Gleason grade, pT stage, pN stage, surgical margin status and preoperative PSA. In conclusion, the results of our study demonstrate that expression of FAM13C is an independent prognostic marker in prostate cancer. Finding FAM13C also in non-neoplastic prostate tissues highlights the importance of properly selecting cancer-rich areas for RNA-based FAM13C expression analysis.

Current application and future perspectives of prostate specific membrane antigen PET imaging in prostate cancer

As precision medicine evolves, the contribution of molecular imaging to the management of prostate cancer (PCa) patients, especially for positron-emission tomography (PET) imaging, is gaining importance. Highly successful approaches to measure the expression of the prostate specific membrane antigen (PSMA) have been introduced recently. PSMA, the glutamate carboxypeptidase II, is a membrane bound metallo-peptidase that is overexpressed in 90-100% of PCa cells. Due to its selective over-expression, PSMA is a reliable tissue marker for prostate cancer and is considered an ideal target for tumor specific imaging and therapy. A variety of PET and SPECT probes targeting this peptide receptor have been introduced. These are undergoing extensive clinical evaluations. Initial results attest to a high accuracy for disease detection compared conventional radiology (CT or MRI) and other nuclear medicine procedure (choline PET or fluciclovine PET). However, prospective evaluation of the impact on patient management for PSMA-ligand PET and its impact on patient outcome is currently missing. Finally, PSMA inhibitors can be radio-labeled with diagnostic (68Ga-PSMA-11), or therapeutic nuclides (177Lu/225Ac PSMA-617) to be used as theranostic agent. Initial results showed that PSMA-targeted radioligand therapy can potentially delay disease progression in metastatic castrate-resistant PCa. This review aims to explore the current application of PSMA based imaging in prostate cancer, reporting about main advantages and limitations of this new theranostic procedure. The future perspectives and potential the applications of this agent will be also discussed.

Molecular Profiling of Pooled Circulating Tumor Cells from Prostate Cancer Patients Using a Dual-Antibody-Functionalized Microfluidic Device

To capture both epithelial and mesenchymal subpopulations of CTCs at different metastatic stages of PCa patients, here we constructed a novel dual-antibody-functionalized microfluidic device by employing antibodies against PSMA and EpCAM. In vitro experiments with the dual capture system for capturing both LnCAP and LnCAP-EMT cells have shown significantly enhanced capture efficiency as compared to that of the EpCAM single capture system. Furthermore, the dual capture system could successfully identify CTCs in 20 out of 24 (83.3%) PCa patients, and the CTCs counts from the dual capture system were statistically correlated with the TNM stage of patients ( P < 0.05), while conventional diagnostic methods, such as serum PSA level and Gleason score, failed to correlate to patient TNM stages. To further explore potential clinical application of our dual capture system, captured CTCs were recovered and subjected to qRT-PCR to quantify known factors involved in PCa development and therapy. The results demonstrated that the combined detection of SChLAP1 and PSA in CTCs is a potential marker for identifying patients with metastatic PCa, while detection of AR and PD-L1 in CTCs may have the potential to determine the sensitivity of PCa patients to androgen deprivation therapy and immunotherapy, respectively. Taken together, the dual-antibody-functionalized microfluidic device established in our study overcomes the limitations of some CTC capture platforms that only detect epithelial or mesenchymal CTCs in PCa patients, and detection of the PCa-related RNA signatures from purified CTCs holds great promise to offer warnings for early metastasis of PCa and may provide guidance for therapy decisions.

p16 overexpression and 9p21 deletion are linked to unfavorable tumor phenotype in breast cancer

Overexpression of the p16 tumor suppressor, but also deletion of its gene locus 9p21, is linked to unfavorable tumor phenotype and poor prognosis in breast cancer. To better understand these contradictory observations, and to clarify the prognostic impact of p16 expression and 9p21 deletion, a tissue microarray (TMA) with 2,197 breast cancers was analyzed by fluorescence in-situ hybridization and immunohistochemistry (FISH) for 9p21 deletion and p16 expression. p16 immunostaining was weak in 25.6%, moderate in 7.1%, and strong in 12.7% of 1,684 evaluable cancers. Strong p16 staining was linked to advanced tumor stage (p = 0.0003), high-grade (p < 0.0001), high tumor cell proliferation (p < 0.0001), negative hormone receptor (ER/PR) status (p < 0.0001 each), and shorter overall survival (p = 0.0038). 9p21 deletion was found in 15.3% of 1,089 analyzable breast cancers, including 1.7% homozygous and 13.6% heterozygous deletions. 9p21 deletion was linked to adverse tumor features, including high-grade (p < 0.0001) and nodal positive cancers (p = 0.0063), high cell proliferation (p < 0.0001), negative hormone receptor (ER/PR) status (p ≤ 0.0006), and HER2 amplification (p = 0.0078). Patient outcome was worse in 9p21 deleted than in undeleted cancers (p = 0.0720). p16 expression was absent in cancers harboring homozygous 9p21 deletions, but no difference in p16 expression was found between cancers with (59.2% p16 positive) and without heterozygous 9p21 deletion (51.3% p16 positive, p = 0.0256). In summary, p16 expression is unrelated to partial 9p21 deletion, but both alterations are linked to aggressive breast cancer phenotype. High-level p16 expression is a strong predictor of unfavorable disease course in breast cancer.

Diagnostic performance of 68Gallium-PSMA-11 PET/CT to detect significant prostate cancer and comparison with 18FEC PET/CT

Background

Radiolabeled prostate-specific membrane antigen (PSMA) has proven to be a highly accurate method to detect recurrence and metastases of prostate cancer, but only sparse data is available about its performance in the diagnosis of clinically significant primary prostate cancer.

Methods

We compared ⁶⁸Ga-PSMA-11 PET/CT in 25 patients with ¹⁸FEC PET/CT in 40 patients with suspected prostate carcinoma based on an increased PSA level.The PET/CT results were compared with the histopathologic Gleason Score (GS) of biopsies.

Results

The ⁶⁸Ga-PSMA-11 PET/CT revealed highly suspect prostatic lesions (maximum standardized uptake value/SUV_max >2.5) in 21/25 patients (84%), associated with GS≥6 (low-grade/high-grade carcinoma). Two histopathologic non-malignancy-relevant cases (GS<6) had PSMA-SUV_max ≤2.5; all histopathologic high-grade cases (GS≥7b) showed PSMA-SUV_max >12.0 which further increased with rising GS. There were 2 false positives and no false negative findings for high-grade prostate cancer using a cut off-level for SUV_max of 2.5.In contrast, the ¹⁸FEC PET/CT showed suspected malignant lesions in 38/40 patients (95%), which included 3 lesions with GS<6. The mean SUV_max values did not differ with different GS. There were 11 false positives and 1 false negative for detection of high-grade prostate cancer (cut off 2.5).By means of ROC analysis a SUV_max of 5.4 was found to be an optimal cut off-level to distinguish between low- and high-grade carcinoma in ⁶⁸Ga-PSMA-11 PET/CT (AUC=0.9692; 95% CI 0.9086;1.0000;SD(AUC)=0.0309)). Choosing a cut off-level of SUV_max5.4, ⁶⁸Ga-PSMA-11 PET/CT was able to distinguish between GS ≤7a/≥7b with a sensitivity of 84%, a specificity of 100%, a negative predictive value (NPV) of 67%, and an efficiency of 88% (p<0.001).The ROC analysis revealed a SUV_max 6.5 as an optimal cut off-level to distinguish between low- and high-grade carcinoma in ¹⁸FEC PET/CT (AUC=0.7470; 95% CI 0.5919;0.9020;SD(AUC)=0.0791) with a sensitivity of 61% and a specificity of 92%; but the efficiency was only 70% and the NPV 50% (p=0.01).

Conclusion

⁶⁸Ga-PSMA-11 PET/CT guided biopsy of the prostate increases diagnostic precision and is likely to help to reduce overtreatment of low-grade malignant disease as well as detect the foci of the highest Gleason pattern. Both methods (⁶⁸Ga-PSMA-11,¹⁸FEC) were suitable to detect primary prostate cancer, but the excellent image quality, the higher specificity and the good correlation of positive scans with GS are advantages of ⁶⁸Ga-PSMA-11.

Targetable Clinical Nanoparticles for Precision Cancer Therapy Based on Disease-Specific Molecular Inflection Points

Novel translational approaches based on clinical modular nanoplatforms are needed in order to treat solid cancers according to their discrete molecular features. In the present study, we show that the clinical nanopharmaceutical Ferumoxytol, which consists of a glucose-based coat surrounding an iron oxide core, could identify molecular characteristics of prostate cancer, corresponding to unique phases of the disease continuum. By affixing a targeting probe for the prostate-specific membrane antigen on its surface, the nanopharmaceutical was able to assess the functional state of the androgen receptor pathway via MRI, guiding therapy and delivering it with the same clinical nanoparticle. In order to simultaneously inhibit signaling from key oncogenic pathways of more advanced forms of prostate cancer, a single-agent therapy for early stage disease to inhibit DNA replication, as well as combination therapy with two drugs co-retained within the nanopharmaceutical's polymeric coating, were tested and resulted in complete tumor ablation. Recalcitrant and terminal forms of the disease were effectively treated with a nanopharmaceutical delivering a combination that upregulates endoplasmic reticulum stress and inhibits metastasis, thereby showing that this multifunctional nanoplatform can be used in the clinic for patient stratification, as well as precision treatment based on the individual's unique disease features.

High-Level Glyoxalase 1 (GLO1) expression is linked to poor prognosis in prostate cancer

BACKGROUND

Glyoxalase 1 (GLO1) is an enzyme involved in removal of toxic byproducts accumulating during glycolysis from the cell. GLO1 is up regulated in many cancer types but its role in prostate cancer is largely unknown.

METHODS

Here, we employed GLO1 immunohistochemistry on a tissue microarray including 11 152 tumors and an attached clinical and molecular database.

RESULTS

Normal prostate epithelium was negative for GLO1, whereas 2059 (27.3%) of 7552 interpretable cancers showed cytoplasmic GLO1 staining, which was considered weak in 8.8%, moderate in 12.5%, and strong in 6.1% of tumors. Up regulation of GLO1 was significantly linked to high original Gleason grade, advanced pathological tumor stage and positive lymph node status (P < 0.0001 each). Comparison of GLO1 staining with several common genomic alterations of prostate cancers revealed a strong link between GLO1 up regulation and TMPRSS2:ERG fusion (P < 0.0001) and an ERG-independent association with PTEN deletion (P < 0.0001). GLO1 up regulation was strongly linked to early biochemical recurrence in univariate analysis (P < 0.0001) and predicted poor prognosis independent from most (except from nodal stage) established prognostic parameters in multivariate analysis (P ≤ 0.03).

CONCLUSIONS

GLO1 upregulation is linked to aggressive prostate cancers characterized by ERG fusion and PTEN deletion. The strong and independent prognostic value makes it a promising candidate for routine diagnostic applications either alone or in combination with other markers.

Identifying cancer origin using circulating tumor cells

Circulating tumor cells (CTCs) have become an established clinical evaluation biomarker. CTC count provides a good correlation with the prognosis of cancer patients, but has only been used with known cancer patients, and has been unable to predict the origin of the CTCs. This study demonstrates the analysis of CTCs for the identification of their primary cancer source. Twelve mL blood samples were equally dispensed on 6 CMx chips, microfluidic chips coated with an anti-EpCAM-conjugated supported lipid bilayer, for CTC capture and isolation. Captured CTCs were eluted to an immunofluorescence (IF) staining panel consisting of 6 groups of antibodies: anti-panCK, anti-CK18, anti-CK7, anti-TTF-1, anti-CK20/anti-CDX2, and anti-PSA/anti-PSMA. Cancer cell lines of lung (H1975), colorectal (DLD-1, HCT-116), and prostate (PC3, DU145, LNCaP) were selected to establish the sensitivity and specificity for distinguishing CTCs from lung, colorectal, and prostate cancer. Spiking experiments performed in 2mL of culture medium or whole blood proved the CMx platform can enumerate cancer cells of lung, colorectal, and prostate. The IF panel was tested on blood samples from lung cancer patients (n = 3), colorectal cancer patients (n = 5), prostate cancer patients (n = 5), and healthy individuals (n = 12). Peripheral blood samples found panCK⁺ and CK18⁺ CTCs in lung, colorectal, and prostate cancers. CTCs expressing CK7⁺ or TTF-1⁺, (CK20/ CDX2)⁺, or (PSA/ PSMA)⁺ corresponded to lung, colorectal, or prostate cancer, respectively. In conclusion, we have designed an immunofluorescence staining panel to identify CTCs in peripheral blood to correctly identify cancer cell origin.

Targeting strategies of adenovirus‑mediated gene therapy and virotherapy for prostate cancer (Review)

Prostate cancer (PCa) poses a high risk to older men and it is the second most common type of male malignant tumor in western developed countries. Additionally, there is a lack of effective therapies for PCa at advanced stages. Novel treatment strategies such as adenovirus-mediated gene therapy and virotherapy involve the expression of a specific therapeutic gene to induce death in cancer cells, however, wild-type adenoviruses are also able to infect normal human cells, which leads to undesirable toxicity. Various PCa-targeting strategies in adenovirus-mediated therapy have been developed to improve tumor-targeting effects and human safety. The present review summarizes the relevant knowledge regarding available adenoviruses and PCa-targeting strategies. In addition, future directions in this area are also discussed. In conclusion, although they remain in the early stages of basic research, adenovirus-mediated gene therapy and virotherapy are expected to become important therapies for tumors in the future due to their potential targeting strategies.

68Ga-PSMA-11 PET/CT for prostate cancer staging and risk stratification in Chinese patients

We evaluated the clinical utility of ⁶⁸Ga-PSMA-11 PET/CT for staging and risk stratification of treatment-naïve prostate cancer (PCa) and metastatic castrate-resistant prostate cancer (mCRPC). Twenty-two consecutive patients with treatment-naïve PCa and 18 with mCRPC were enrolled. ⁶⁸Ga-PSMA-11 PET/CT and magnetic resonance imaging (MRI) were performed for the evaluation of primary prostatic lesions, and bone scans were used for evaluation bone metastasis. Among the 40 patients, 37 (92.5% [22 treatment-naïve PCa, 15 mCRPC]) showed PSMA-avid lesions on ⁶⁸Ga-PSMA-11 images. Only 3 patients with stable mCRPC after chemotherapy were negative for PSMA. The sensitivity, specificity and accuracy of ⁶⁸Ga-PSMA-11 imaging were 97.3%, 100.0% and 97.5%, respectively. The maximum standardized uptake (SUV_max) of prostatic lesions was 17.09 ± 11.08 and 13.33 ± 12.31 in treatment-naïve PCa and mCRPC, respectively. ⁶⁸Ga-PSMA-11 revealed 105 metastatic lymph nodes in 15 patients; the SUV_max was 16.85 ± 9.70 and 7.54 ± 5.20 in treatment-naïve PCa and mCRPC, respectively. ⁶⁸Ga-PSMA-11 PET/CT also newly detected visceral metastasis in 9 patients (22.5%) and bone metastasis in 29 patients (72.5%). ⁶⁸Ga-PSMA-11 PET/CT exhibits potential for staging and risk stratification in naïve PCa, as well as improved sensitivity for detection of lymph node and remote metastasis.

Increased ERCC1 expression is linked to chromosomal aberrations and adverse tumor biology in prostate cancer

BACKGROUND

Animal model experiments have suggested a role of the DNA repair protein ERCC1 (Excision Repair Cross-Complementation Group 1) in prostate cancer progression.

METHODS

To better understand the impact of ERCC1 protein expression in human prostate cancer, a preexisting tissue microarray (TMA) containing more than 12,000 prostate cancer specimens was analyzed by immunohistochemistry and data were compared with tumor phenotype, PSA recurrence and several of the most common genomic alterations (TMPRSS2:ERG fusions: deletions of PTEN, 6q, 5q, 3p).

RESULTS

ERCC1 staining was seen in 64.7% of 10,436 interpretable tissues and was considered weak in 37.1%, moderate in 22.6% and strong in 5% of tumors. High-level ERCC1 staining was linked to advanced pT stage, high Gleason grade, positive lymph nodes, high pre-operative serum PSA, and positive surgical margin status (p < 0.0001 each). High ERCC1 expression was strongly associated with an elevated risk of PSA recurrence (p < 0.0001). This was independent of established prognostic features. A subgroup analysis of cancers defined by comparable quantitative Gleason grades revealed that the prognostic impact was mostly driven by low-grade tumors with a Gleason 3 + 3 or 3 + 4 (Gleason 4: ≤5%). High ERCC1 expression was strongly associated with the presence of genomic alterations and expression levels increased with the number of deletions present in the tumor. These latter data suggest a functional relationship of ERCC1 expression with genomic instability.

CONCLUSION

The results of our study demonstrate that expression of ERCC1 - a potential surrogate for genomic instability - is an independent prognostic marker in prostate cancer with particular importance in low-grade tumors.

SERCA control of cell death and survival

Intracellular calcium (Ca²⁺⁾ is a critical coordinator of various aspects of cellular physiology. It is increasingly apparent that changes in cellular Ca²⁺ dynamics contribute to the regulation of normal and pathological signal transduction that controls cell growth and survival. Aberrant perturbations in Ca²⁺ homeostasis have been implicated in a range of pathological conditions, such as cardiovascular diseases, diabetes, tumorigenesis and steatosis hepatitis. Intracellular Ca²⁺ concentrations are therefore tightly regulated by a number of Ca²⁺ handling enzymes, proteins, channels and transporters located in the plasma membrane and in Ca²⁺ storage organelles, which work in concert to fine tune a temporally and spatially precise Ca²⁺ signal. Chief amongst them is the sarco/endoplasmic reticulum (SR/ER) Ca²⁺ ATPase pump (SERCA) which actively re-accumulates released Ca²⁺ back into the SR/ER, therefore maintaining Ca²⁺ homeostasis. There are at least 14 different SERCA isoforms encoded by three ATP2A1-3 genes whose expressions are species- and tissue-specific. Altered SERCA expression and activity results in cellular malignancy and induction of ER stress and ER stress-associated apoptosis. The role of SERCA misregulation in the control of apoptosis in various cell types and disease setting with prospective therapeutic implications is the focus of this review. Ca²⁺ is a double edge sword for both life as well as death, and current experimental evidence supports a model in which Ca²⁺ homeostasis and SERCA activity represent a nodal point that controls cell survival. Pharmacological or genetic targeting of this axis constitutes an incredible therapeutic potential to treat different diseases sharing similar biological disorders.

177Lu-PSMA Radioligand Therapy for Prostate Cancer

¹⁷⁷Lu-prostate-specific membrane antigen (PSMA) radioligand therapy (RLT) using inhibitors of PSMA is a novel therapeutic option in patients with metastatic castration-resistant prostate cancer. The current literature suggests that this therapy is well tolerated and effective. On the basis of clinical need and current evidence, the therapy is being implemented in a growing number of centers worldwide. Here, we review important aspects of ¹⁷⁷Lu-PSMA RLT, including patient stratification, the therapy protocol, concomitant medication, and follow-up, to inform medical staff involved in the RLT and care of patients with metastatic castration-resistant prostate cancer.

Diagnostic performance of 68Ga-PSMA-11 (HBED-CC) PET/CT in patients with recurrent prostate cancer: evaluation in 1007 patients

Purpose

Since the clinical introduction of ⁶⁸Ga-PSMA-11 PET/CT, this imaging method has rapidly spread and is now regarded as a significant step forward in the diagnosis of recurrent prostate cancer (PCa). The aim of this study was to analyse the influence of several variables with possible influence on PSMA ligand uptake in a large cohort.

Methods

We performed a retrospective analysis of 1007 consecutive patients who were scanned with ⁶⁸Ga-PSMA-11 PET/CT (1 h after injection) from January 2014 to January 2017 to detect recurrent disease. Patients with untreated primary PCa or patients referred for PSMA radioligand therapy were excluded. The possible effects of different variables including PSA level and PSA doubling time (PSA_DT), PSA velocity (PSA_Vel), Gleason score (GSC, including separate analysis of GSC 7a and 7b), ongoing androgen deprivation therapy (ADT), patient age and amount of injected activity were evaluated.

Results

In 79.5% of patients at least one lesion with characteristics suggestive of recurrent PCa was detected. A pathological (positive) PET/CT scan was associated with PSA level and ADT. GSC, amount of injected activity, patient age, PSA_DT and PSA_Vel were not associated with a positive PET/CT scan in multivariate analysis.

Conclusion

⁶⁸Ga-PSMA-11 PET/CT detects tumour lesions in a high percentage of patients with recurrent PCa. Tumour detection is clearly associated with PSA level and ADT. Only a tendency for an association without statistical significance was found between higher GSC and a higher probability of a pathological PET/CT scan. No associations were found between a pathological ⁶⁸Ga-PSMA-11 PET/CT scan and patient age, amount of injected activity, PSA_DT or PSA_Vel.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-017-3711-7) contains supplementary material, which is available to authorized users.