Neuroendocrine tumors of the prostate

Reassessing the Role of Low PSA in Prognosis Across Grades of Prostate Cancer: A Cohort Study

BACKGROUND

Prior studies have concentrated exclusively on how different prostate-specific antigen (PSA) levels affect the prognosis of high-grade prostate cancer (PCa), often overlooking the prognosis of low-grade PCa.

METHODS

The present cohort study included individuals diagnosed with PCa from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2021. The all-cause mortality (ACM) and prostate cancer-specific mortality (PCSM) for each treatment group was calculated stratified by the four PSA levels (≤ 4.0, 4.1-10.0, 10.1-20.0, and > 20.0 ng/mL). Fine and Gray competing-risks analyses were conducted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Cox proportional hazards regression analyses using PSA as a continuous variable with restricted cubic splines (RCS) were conducted to allow for potential nonlinear relationships.

RESULTS

This study encompassed 416,825 male patients diagnosed with PCa. Compared to individuals with PSA value between 4.1 and 10.0 ng/mL, a significant association between low levels of PSA (≤ 4.0 ng/mL) and an increased risk of ACM (AHR = 1.15, 95% CI: 1.12-1.19; p < 0.001) and PCSM (AHR = 1.49, 95% CI: 1.38-1.61; p < 0.001) was observed. Additionally, the increased risk of ACM (AHR = 1.35, 95% CI: 1.29-1.40; p < 0.001) and PCSM (AHR = 1.84, 95% CI: 1.67-2.02; p < 0.001) are more pronounced within the first 5 years post-diagnosis. In most subgroups, similar results were observed. The RCS curves further corroborated the correlation between PSA value and the risk of mortality.

CONCLUSION

Low PSA levels are notably linked to a heightened risk for both ACM and PCSM, irrespective of the grade of PCa being high or low. There is a need to initiate new studies that tackle novel diagnostics and therapeutics.

Current and future directions in theranostics for neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is rare at the time of initial diagnosis but much more common in patients treated with the combination of androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPI) such as abiraterone and enzalutamide. NEPC is typically characterized by the loss of prostate-specific membrane antigen (PSMA) expression while exhibiting variable neuroendocrine markers. Recent advancements in nuclear medicine have provided a promising avenue for the development of molecular imaging techniques and targeted therapies tailored to NEPC. This review examines the current and future role of theranostics in the diagnosis and management of NEPC and explores potential future directions in this rapidly evolving field.

Epigenomics-guided precision oncology: Chromatin variants in prostate tumor evolution

Prostate cancer is a common malignancy that in 5%-30% leads to treatment-resistant and highly aggressive disease. Metastasis-potential and treatment-resistance is thought to rely on increased plasticity of the cancer cells-a mechanism whereby cancer cells alter their identity to adapt to changing environments or therapeutic pressures to create cellular heterogeneity. To understand the molecular basis of this plasticity, genomic studies have uncovered genetic variants to capture clonal heterogeneity of primary tumors and metastases. As cellular plasticity is largely driven by non-genetic events, complementary studies in cancer epigenomics are now being conducted to identify chromatin variants. These variants, defined as genomic loci in cancer cells that show changes in chromatin state due to the loss or gain of epigenomic marks, inclusive of histone post-translational modifications, DNA methylation and histone variants, are considered the fundamental units of epigenomic heterogeneity. In prostate cancer chromatin variants hold the promise of guiding the new era of precision oncology. In this review, we explore the role of epigenomic heterogeneity in prostate cancer, focusing on how chromatin variants contribute to tumor evolution and therapy resistance. We therefore discuss their impact on cellular plasticity and stochastic events, highlighting the value of single-cell sequencing and liquid biopsy epigenomic assays to uncover new therapeutic targets and biomarkers. Ultimately, this review aims to support a new era of precision oncology, utilizing insights from epigenomics to improve prostate cancer patient outcomes.

Failure to progress: breast and prostate cancer cell lines in developing targeted therapies

Developing anticancer drugs from preclinical to clinical takes approximately a decade in a cutting-edge biomedical lab and still 97% of most fail at clinical trials. Cell line usage is critical in expediting the advancement of anticancer therapies. Yet developing appropriate cell lines has been challenging and overcoming these obstacles whilst implementing a systematic approach of utilizing 3D models that recapitulate the tumour microenvironment is prudent. Using a robust and continuous supply of cell lines representing all ethnic groups from all locales is necessary to capture the evolving tumour landscape in culture. Next, the conversion of these models to systems on a chip that can by way of high throughput cytotoxic assays identify drug leads for clinical trials should fast-track drug development while markedly improving success rates. In this review, we describe the challenges that have hindered the progression of cell line models over seven decades and methods to overcome this. We outline the gaps in breast and prostate cancer cell line pathology and racial representation alongside their involvement in relevant drug development.

Long noncoding RNA mediates enzalutamide resistance and transformation in neuroendocrine prostate cancer

Prostate cancer is a malignant tumor caused by the malignant proliferation of epithelial cells, which is highly heterogeneous and drug-resistant, and neuroendocrine prostate cancer (NEPC) is an essential cause of drug resistance in its late stage. Elucidating the evolution of NEPC and the resistance process of enzalutamide, a novel antiandrogen, will be of great help in improving the prognosis of patients. As a research hotspot in the field of molecular biology in recent years, the wide range of biological functions of long noncoding RNAs (lncRNAs) has demonstrated their position in the therapeutic process of many diseases, and a large number of studies have revealed their critical roles in tumor progression and drug resistance. Therefore, elucidating the involvement of lncRNAs in the formation of NEPCs and their interrelationship with enzalutamide resistance may provide new ideas for a deeper understanding of the development of this disease and the occurrence of enzalutamide resistance and give a new direction for reversing the therapeutic dilemma of advanced prostate cancer. This article focuses on lncRNAs that regulate enzalutamide resistance and the neuroendocrine transition of prostate cancer through epigenetic, androgen receptor (AR) signaling, and non-AR pathways that act as "molecular sponges" interacting with miRNAs. Some insights into these mechanisms are used to provide some help for subsequent research in this area.

Neuroendocrine Differentiation in Prostate Cancer Requires ASCL1

Most patients with prostate adenocarcinoma develop resistance to therapies targeting the androgen receptor (AR). Consequently, a portion of these patients develop AR-independent neuroendocrine (NE) prostate cancer (NEPC), a rapidly progressing cancer with limited therapies and poor survival outcomes. Current research to understand the progression to NEPC suggests a model of lineage plasticity whereby AR-dependent luminal-like tumors progress toward an AR-independent NEPC state. Genetic analysis of human NEPC identified frequent loss of RB1 and TP53, and the loss of both genes in experimental models mediates the transition to a NE lineage. Transcriptomics studies have shown that lineage transcription factors ASCL1 and NEUROD1 are present in NEPC. In this study, we modeled the progression of prostate adenocarcinoma to NEPC by establishing prostate organoids and subsequently generating subcutaneous allograft tumors from genetically engineered mouse models harboring Cre-induced loss of Rb1 and Trp53 with Myc overexpression (RPM). These tumors were heterogeneous and displayed adenocarcinoma, squamous, and NE features. ASCL1 and NEUROD1 were expressed within NE-defined regions, with ASCL1 being predominant. Genetic loss of Ascl1 in this model did not decrease tumor incidence, growth, or metastasis; however, there was a notable decrease in NE identity and an increase in basal-like identity. This study provides an in vivo model to study progression to NEPC and establishes the requirement for ASCL1 in driving NE differentiation in prostate cancer. Significance: Modeling lineage transitions in prostate cancer and testing dependencies of lineage transcription factors have therapeutic implications, given the emergence of treatment-resistant, aggressive forms of neuroendocrine prostate cancer. See related commentary by McQuillen and Brady, p. 3499.

Clinicopathological and epigenetic differences between primary neuroendocrine tumors and neuroendocrine metastases in the ovary

Currently, the available literature provides insufficient support to differentiate between primary ovarian neuroendocrine tumors (PON) and neuroendocrine ovarian metastases (NOM) in patients. For this reason, patients with a well-differentiated ovarian neuroendocrine tumor (NET) were identified through electronic patient records and a nationwide search between 1991 and 2023. Clinical characteristics were collected from electronic patient files. This resulted in the inclusion of 71 patients with NOM and 17 patients with PON. Histologic material was stained for Ki67, SSTR2a, CDX2, PAX8, TTF1, SATB2, ISLET1, OTP, PDX1, and ARX. DNA methylation analysis was performed on a subset of cases. All PON were unilateral and nine were found within a teratoma (PON-T+). A total of 78% of NOM were bilateral, and none were associated with a teratoma. PON without teratomous components (PON-T-) displayed a similar insular growth pattern and immunohistochemistry as NOM (p > 0.05). When compared with PON-T+, PON-T- more frequently displayed ISLET1 positivity and were larger, and patients were older at diagnosis (p < 0.05). Unsupervised analysis of DNA methylation profiles from tumors of ovarian (n = 16), pancreatic (n = 22), ileal (n = 10), and rectal (n = 7) origin revealed that four of five PON-T- clustered together with NOM and ileal NET, whereas four of five PON-T+ grouped with rectum NET. In conclusion, unilateral ovarian NET within a teratoma should be treated as a PON. Ovarian NET localizations without teratomous components have a molecular profile analogous to midgut NET metastases. For these patients, a thorough review of imaging should be performed to identify a possible undetected midgut NET and a corresponding follow-up strategy may be recommended.

Unraveling molecular characteristics and tumor microenvironment dynamics of neuroendocrine prostate cancer

Prostate cancer (PCa) is the most prevalent malignancy and the second leading cause of cancer-related deaths among men. While adenocarcinoma of the prostate (adeno-PCa) is well-characterized, neuroendocrine prostate cancer (NEPC) remains poorly understood. Generally, NEPC is a rare but highly aggressive histological variant, however its limited patho-physiological understanding leads to insufficient treatment options associated with low survival rates for NEPC patients. Current treatments for NEPC, including platinum-based therapies, offer some efficacy, but there is a significant need for more targeted approaches. This review summarizes the molecular characteristics of NEPC in contrast to adeno-PCa, providing a comprehensive comparison. A significant portion of the discussion is dedicated to the tumor microenvironment (TME), which has recently been identified as a key factor in tumor progression. The TME includes various cells, signaling molecules, and the extracellular matrix surrounding the tumor, all of which play critical roles in cancer development and response to treatment. Understanding the TME's influence on NEPC could uncover new avenues for innovative treatment strategies, potentially improving outcomes for patients with this challenging variant of PCa.

Remarks on Selected Morphological Aspects of Cancer Neuroscience: A Microscopic Photo Review

BACKGROUND

This short review and pictorial essay presents a morphological insight into cancer neuroscience, which is a complex and dynamic area of the pathobiology of tumors.

METHODS

We discuss the different methods and issues connected with structural research on tumor innervation, interactions between neoplastic cells and the nervous system, and dysregulated neural influence on cancer phenotypes.

RESULTS

Perineural invasion (PNI), the most-visible cancer-nerve relation, is briefly presented, focusing on its pathophysiology and structural diversity as well as its clinical significance. The morphological approach to cancer neurobiology further includes the analysis of neural density/axonogenesis, neural network topographic distribution, and composition of fiber types and size. Next, the diverse range of neurotransmitters and neuropeptides and the neuroendocrine differentiation of cancer cells are reviewed. Another morphological area of cancer neuroscience is spatial or quantitative neural-related marker expression analysis through different detection, description, and visualization methods, also on experimental animal or cellular models.

CONCLUSIONS

Morphological studies with systematic methodologies provide a necessary insight into the structure and function of the multifaceted tumor neural microenvironment and in context of possible new therapeutic neural-based oncological solutions.

Primary Well-Differentiated Neuroendocrine Tumor/Carcinoid of the Prostate: Case Report and Review of Literature

Primary well-differentiated neuroendocrine tumor (WDNT)/carcinoid of the genitourinary tract is rare. Many WDNT reported in the prostate gland have been seen in close association with conventional prostatic adenocarcinoma and/or label for prostate-specific immunohistochemical markers and are best considered prostatic adenocarcinomas with "carcinoid-like" features. We present a case of primary WDNT/carcinoid incidentally detected in a 67-year-old man who underwent radical prostatectomy for Grade group 2 prostatic adenocarcinoma. Morphologically, the neuroendocrine (NE) lesion appeared distinct from the prostatic adenocarcinoma, labeled for NE markers, was negative for prostatic markers (NKX3.1, PSA, and ERG), and showed an overall low Ki-67 proliferation index (<1%). Follow-up was uneventful with no evidence of residual disease or metastasis.

Impact of Neuroendocrine Differentiation (NED) on Enzalutamide and Abiraterone Efficacy in Metastatic Castration-Resistant Prostate Cancer (mCRPC): A Retrospective Analysis

Neuroendocrine differentiation (NED) represents a possible androgen receptor pathway inhibitors (ARPI) resistance mechanism in metastatic castration resistance prostate cancer (mCRPC). As mCRPC with NED has been excluded from clinical trials evaluating ARPI efficacy, this study investigates the prognostic impact of NED in mCRPC patients treated with ARPIs. Methods: We retrospectively analyzed 327 mCRPC patient data treated with Enzalutamide or Abiraterone in the first and second or successive lines of treatment. NED was assessed using prostate biopsy samples through immunohistochemical staining. Results: NED was confirmed in 32/327 (9.8%) mCRPC patients. In the overall population, mCRPC with NED showed worse PFS (4.38 vs. 11.48 months HR 2.505 [1.71-3.68] p < 0.05), disease control rate (DCR), and PSA response. In the first line setting, mCRPC with NED demonstrated worse PFS (8.5 vs. 14.9 months HR 2.13 [1.18-3.88], p < 0.05). Similarly, in the second or successive lines, mCRPC with NED showed worse PFS (4.0 vs. 7.5 months HR 2.43 [1.45-4.05] p < 0.05), DCR, PSA response and OS (12.53 vs. 18.03 months HR 1.86 [1.12-3.10] p < 0.05). The adverse impact of NED on PFS was consistence across all subgroups; we also noted a trend of worse PFS in patients with high vs. low NED. Conclusions: In our study, mCRPC with NED treated with Enzalutamide or Abiraterone showed worse clinical outcomes. NED assessment should be considered to optimize treatment decisions in the mCRPC setting.

Prognostic Nomogram Predicting Survival and Propensity Score Matching with Demographics and Comparative Analysis of Prostate Small Cell and Large Cell Neuroendocrine Carcinoma

Background: This retrospective study aims to examine the patient demographics, survival rates, and treatment methods for small-cell neuroendocrine carcinoma (SCNEC) and large-cell neuroendocrine carcinoma (LCNEC) of prostate origin while also identifying the main differences between common types of prostate cancer with comparative analysis for survival. Methods: Our analysis utilized the Surveillance, Epidemiology, and End Results database (SEER), and data was collected from 2000-2020. Cox proportional hazards and chi-squared analysis were used for statistical analysis. Results: A total of 718 cases of prostate small and large neuroendocrine carcinoma were identified. The median age was 71.5 years, and the median follow-up was 11.0 years (95% confidence interval (95% CI) = 9.2-12.8). Most patients were over the age of 80 years (33.8%) and Caucasian (74.4%). The overall 5-year survival was 8.0% (95% CI = 6.8-9.2). The 5-year OS for Caucasians was 7.3% (95% C.I. 6.0-8.3). For Black Americans, the 5-year OS was 11.9% (95% C.I. 7.3-16.5). For Hispanics, the 5-year OS was 12.2% (95% C.I. 7.7-16.7). The 5-year cause-specific survival (CSS) was 16.2% (95% CI = 14.3-18.1). For treatment modality, the five-year survival for each were as follows: chemotherapy, 3.5% (95% CI = 2.1-4.9); surgery, 18.2% (95% CI = 13.6-22.8); multimodality therapy (surgery and chemotherapy), 4.8% (95% CI = 1.7-7.9); and combination (chemoradiation with surgery), 5.0% (95% CI = 1.0-9.0). The prognostic nomogram created to predict patient survivability matched the findings from the statistical analysis with a statistical difference found in race, income, housing, stage, and nodal status. The nomogram also indicated a slight increase in mortality with tumors of greater size. This analysis showed a slight increase in mortality for patients of Asian race. In addition, there was a significant increase in death for patients with stage 3 tumors, as well as patients who underwent surgery and radiation. Furthermore, we performed propensity score matching for survival differences, and no survival difference was found between SCNEC and LCNEC. Conclusions: Asian patients, larger tumor size, and distant disease were associated with worse long-term clinical outcomes. By leveraging insights from registry-based studies, clinicians can better strategize treatment options, improving patient outcomes in this challenging oncology arena.

Lethal disseminated intravascular coagulation induced by primary and metastatic neuroendocrine prostate cancer

Introduction

Neuroendocrine prostate cancer has a poor prognosis. Although disseminated intravascular coagulation associated with malignancy can be lethal, it very rarely occurs among patients with primary neuroendocrine prostate cancer.

Case presentation

An 80-year-old man presented to our hospital with bloody sputum. Blood examination indicated disseminated intravascular coagulation. Serum levels of prostate-specific antigen and neuron-specific enolase were 44.274 and 176 ng/mL, respectively. Core needle biopsies of an irregular mass in the prostate and a metastatic tumor in the left iliac bone showed similar neuroendocrine carcinoma cells. Hence, the patient was diagnosed with disseminated intravascular coagulation associated with primary and metastatic neuroendocrine prostate cancer. Unfortunately, he passed away 3 weeks after the biopsies.

Conclusion

Given the difficulty of effectively treating metastatic neuroendocrine prostate cancer among patients in poor physical condition due to disease progression, identifying a new well-tolerated treatment modality is imperative.

Patterns of Immunoreactivity with TTF-1 Antibodies 8G7G3/1 and SPT24 Suggest Distinct Immunoprofiles Between Most Pulmonary and Nonpulmonary Small Cell Carcinomas

Introduction. Small cell carcinoma can arise from various sites. Herein, we analyze the ability of 2 thyroid transcription factor-1 (TTF-1) antibodies (SPT24 and 8G7G3/1) to separate pulmonary from nonpulmonary small cell carcinoma. Materials and Methods. We analyzed 26 pulmonary and 83 nonpulmonary small cell carcinomas, and 14 Merkel cell carcinomas. Each tumor was stained with SPT24 and 8G7G3/1. Extent of nuclear staining was scored as diffuse (>50%), focal (11%-50%), rare (1%-10%), or negative (<1%). Results. All pulmonary small cell carcinomas were positive for SPT24 and 8G7G3/1. Four Merkel cell carcinomas (29%) were positive for SPT24 (ranging from rare-to-diffuse), while 2 (14%) showed rare expression with 8G7G3/1. For nonpulmonary small cell carcinomas, 69 (83%) were positive for SPT24 and 40 (48%) were positive for 8G7G3/1. For SPT24 positive tumors, the extent of 8G7G3/1 expression was equal in 17 (25%) and less in 52 tumors (75%), including 29 (42%) that were negative for 8G7G3/1. No nonpulmonary small cell carcinoma had more staining with 8G7G3/1 compared to SPT24. The differences in staining between 8G7G3/1 and SPT24 in the nonpulmonary cohort were statistically significant (P < 0.0001) with no significant difference between primary and metastatic lesions for 8G7G3/1 (P  =  0.66) or SPT24 (P  =  0.77). Conclusion. Most pulmonary small cell carcinomas are diffusely positive for both SPT24 and 8G7G3/1, whereas most nonpulmonary small cell carcinomas exhibit focal-to-no staining with 8G7G3/1 and significantly less staining with 8G7G3/1 compared to SPT24. However, these trends are not absolute and should be interpreted in conjunction with clinical and radiological findings.

Treatment-related Neuroendocrine Prostate Carcinoma-Diagnostic and Molecular Correlates

Treatment-related neuroendocrine prostate cancer is a distinctive category of prostate cancer that arises after intensive suppression of the androgen receptor by next-generation therapeutic inhibition of androgen receptor signaling. The biological processes that set in motion the series of events resulting in transformation of adenocarcinoma to neuroendocrine carcinoma include genomic (loss of tumor suppressors TP53 and RB1, amplification of oncogenes N-MYC and Aurora Kinase A, dysregulation of transcription factors SOX2, achaete-scute-homolog 1, and others) as well as epigenomic (DNA methylation, EZH2 overexpression, and others). Pathologic diagnosis is key to effective therapy for this disease, and this is aided by localizing metastatic lesions for biopsy using radioligand imaging in the appropriate clinical context. As our understanding of biology evolves, there has been increased morphologic recognition and characterization of tumor phenotypes that are present in this advanced post-treatment setting. New and promising biomarkers (delta-like ligand 3 and others) have been discovered, which opens up novel therapeutic avenues including immunotherapy and antibody-drug conjugates for this lethal disease with currently limited treatment options.

Intra-prostatic tumour evolution, steps in metastatic spread and histogenomic associations revealed by integration of multi-region whole-genome sequencing with histopathological features

BACKGROUND

Extension of prostate cancer beyond the primary site by local invasion or nodal metastasis is associated with poor prognosis. Despite significant research on tumour evolution in prostate cancer metastasis, the emergence and evolution of cancer clones at this early stage of expansion and spread are poorly understood. We aimed to delineate the routes of evolution and cancer spread within the prostate and to seminal vesicles and lymph nodes, linking these to histological features that are used in diagnostic risk stratification.

METHODS

We performed whole-genome sequencing on 42 prostate cancer samples from the prostate, seminal vesicles and lymph nodes of five treatment-naive patients with locally advanced disease. We spatially mapped the clonal composition of cancer across the prostate and the routes of spread of cancer cells within the prostate and to seminal vesicles and lymph nodes in each individual by analysing a total of > 19,000 copy number corrected single nucleotide variants.

RESULTS

In each patient, we identified sample locations corresponding to the earliest part of the malignancy. In patient 10, we mapped the spread of cancer from the apex of the prostate to the seminal vesicles and identified specific genomic changes associated with the transformation of adenocarcinoma to amphicrine morphology during this spread. Furthermore, we show that the lymph node metastases in this patient arose from specific cancer clones found at the base of the prostate and the seminal vesicles. In patient 15, we observed increased mutational burden, altered mutational signatures and histological changes associated with whole genome duplication. In all patients in whom histological heterogeneity was observed (4/5), we found that the distinct morphologies were located on separate branches of their respective evolutionary trees.

CONCLUSIONS

Our results link histological transformation with specific genomic alterations and phylogenetic branching. These findings have implications for diagnosis and risk stratification, in addition to providing a rationale for further studies to characterise the genetic changes causally linked to morphological transformation. Our study demonstrates the value of integrating multi-region sequencing with histopathological data to understand tumour evolution and identify mechanisms of prostate cancer spread.

Experience and Lessons Learned in the Treatment of Transforming Small Cell Neuroendocrine Carcinoma of the Prostate: A Case Report and Literature Review

Introduction

Small cell neuroendocrine carcinoma of the prostate (SCNECP) is a rare and highly malignant tumor that commonly transforms into conventional prostate adenocarcinoma (CPAC). Most of SCNECP cases cannot be detected and diagnosed early, and SCNECP is often diagnosed when there is liver and lung metastasis. Therefore, the early detection of the process from CPAC to SCNECP is crucial.

Case Report

We present a case of a 73-year-old man who was initially admitted to our hospital with metastatic CPAC. He was administered goserelin acetate 3.6 mg combined with bicalutamide tablets (50 mg) once daily for endocrine therapy and docetaxel (100 mg) combined with prednisone (5 mg) twice a day. After treatment, the prostate-specific antigen (PSA) level decreased significantly, but the CEA, CA199, and CA125 levels began to increase progressively after a short decline. However, no solid tumor recurrence was observed in multiple reexaminations. It was not until 9 months after the elevation of tumor markers that multiple metastatic lesions appeared in the liver, which finally confirmed the diagnosis of metastatic SCNECP. After chemotherapy with etoposide 360 mg combined with carboplatin 200 mg, the tumor size was significantly reduced, and tumor markers decreased. However, the remission time was only 3 months. The patient's liver metastases continued to grow, and CEA, CA199, and CA125 levels continued to increase.

Conclusion

During CPAC treatment, PSA levels continued to decrease, whereas CEA, CA199, and CA125 levels continued to increase. This suggests the possibility of the transformation of CPAC into SCNECP.

Loss of PDE4D7 expression promotes androgen independence, neuroendocrine differentiation and alterations in DNA repair: implications for therapeutic strategies

BACKGROUND

Androgen signalling remains the seminal therapeutic approach for the management of advanced prostate cancer. However, most tumours eventually shift towards an aggressive phenotype, characterised by androgen independence and treatment resistance. The cyclic adenosine monophosphate (cAMP) pathway plays a crucial role in regulating various cellular processes, with the phosphodiesterase PDE4D7 being a vital modulator of cAMP signalling in prostate cancer cells.

METHODS

Using shRNA-mediated PDE4D7 knockdown in LNCaP cells and downstream analysis via RNA sequencing and phenotypic assays, we replicate clinical observations that diminished PDE4D7 expression promotes an aggressive prostate cancer phenotype.

RESULTS

Our study provides evidence that loss of PDE4D7 expression represents a pivotal switch driving the transition from an androgen-sensitive state to hormone unresponsiveness and neuroendocrine differentiation. In addition, we demonstrate that PDE4D7 loss affects DNA repair pathways, conferring resistance to poly ADP ribose polymerase (PARP) inhibitors.

CONCLUSION

Reinstating PDE4D7 expression sensitises prostate cancer cells to anti-androgens, DNA damage response inhibitors, and cytotoxic therapies. These findings provide significant insight into the regulatory role of PDE4D7 in the development of lethal prostate cancer and the potential of its modulation as a novel therapeutic strategy.

Reporting Trends, Practices, and Resource Utilization in Neuroendocrine Tumors of the Prostate Gland: A Survey among Thirty-Nine Genitourinary Pathologists

Background. Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods. Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results. A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion. There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland.

PET radiotracers for whole-body in vivo molecular imaging of prostatic neuroendocrine malignancies

Prostatic neuroendocrine malignancies represent a spectrum of diseases. Treatment-induced neuroendocrine differentiation (tiNED) in hormonally treated adenocarcinoma has been the subject of a large amount of recent research. However, the identification of neuroendocrine features in treatment-naïve prostatic tumor raises a differential diagnosis between prostatic adenocarcinoma with de novo neuroendocrine differentiation (dNED) versus one of the primary prostatic neuroendocrine tumors (P-NETs) and carcinomas (P-NECs). While [18F]FDG is being used as the main PET radiotracer in oncologic imaging and reflects cellular glucose metabolism, other molecules labeled with positron-emitting isotopes, mainly somatostatin-analogues labeled with 68Ga and prostate-specific membrane antigen (PSMA)-ligands labeled with either 18F or 68Ga, are now routinely used in departments of nuclear medicine and molecular imaging, and may be advantageous in imaging prostatic neuroendocrine malignancies. Still, the selection of the preferred PET radiotracer in such cases might be challenging. In the current review, we summarize and discuss published data on these different entities from clinical, biological, and molecular imaging standpoints. Specifically, we review the roles that [18F]FDG, radiolabeled somatostatin-analogues, and radiolabeled PSMA-ligands play in these entities in order to provide the reader with practical recommendations regarding the preferred PET radiotracers for imaging each entity. In cases of tiNED, we conclude that PSMA expression may be low and that [18F]FDG or radiolabeled somatostatin-analogues should be preferred for imaging. In cases of prostatic adenocarcinoma with dNED, we present data that support the superiority of radiolabeled PSMA-ligands. In cases of primary neuroendocrine malignancies, the use of [18F]FDG for imaging high-grade P-NECs and radiolabeled somatostatin-analogues for imaging well-differentiated P-NETs is recommended. KEY POINTS: • The preferred PET radiotracer for imaging prostatic neuroendocrine malignancies depends on the specific clinical scenario and pathologic data. • When neuroendocrine features result from hormonal therapy for prostate cancer, PET-CT should be performed with [18F]FDG or radiolabeled somatostatin-analogue rather than with radiolabeled PSMA-ligand. • When neuroendocrine features are evident in newly diagnosed prostate cancer, differentiating adenocarcinoma from primary neuroendocrine malignancy is challenging but crucial for selection of PET radiotracer and for clinical management.

PET imaging of new target CDK19 in prostate cancer

PURPOSE

Prostate-specific membrane antigen (PSMA)-positron emission tomography (PET) is a superior method to predict patients' risk of cancer progression and response to specific therapies. However, its performance is limited for neuroendocrine prostate cancer (NEPC) and PSMA-low prostate cancer cells, resulting in diagnostic blind spots. Hence, identifying novel specific targets is our aim for diagnosing those prostate cancers with low PSMA expression.

METHODS

The Cancer Genome Atlas (TCGA) database and our cohorts from men with biopsy-proven high-risk metastatic prostate cancer were used to identify CDK19 and PSMA expression. PDX lines neP-09 and P-16 primary cells were used for cellular uptake and imaging mass cytometry in vitro. To evaluate in vivo CDK19-specific uptake of gallium(Ga)-68-IRM-015-DOTA, xenograft mice models and blocking assays were used. PET/CT imaging data were obtained to estimate the absorbed dose in organs.

RESULTS

Our study group had reported the overexpression of a novel tissue-specific gene CDK19 in high-risk metastatic prostate cancer and CDK19 expression correlated with metastatic status and tumor staging, independently with PSMA and PSA levels. Following up on this new candidate for use in diagnostics, small molecules targeting CDK19 labeled with Ga-68 (68Ga-IRM-015-DOTA) were used for PET in this study. We found that the 68Ga-IRM-015-DOTA was specificity for prostate cancer cells, but the other cancer cells also took up little 68Ga-IRM-015-DOTA. Importantly, mouse imaging data showed that the NEPC and CRPC xenografts exhibited similar signal strength with 68Ga-IRM-015-DOTA, but 68Ga-PSMA-11 only stained the CRPC xenografts. Furthermore, target specificity was elucidated by a blocking experiment on a CDK19-bearing tumor xenograft. These data concluded that 68Ga-CDK19 PET/CT was an effective technology to detect lesions with or without PSMA in vitro, in vivo, and in the PDX model.

CONCLUSION

Thus, we have generated a novel PET small molecule with predictive value for prostate cancer. The findings indicate that 68Ga-CDK19 may merit further evaluation as a predictive biomarker for PET scans in prospective cohorts and may facilitate the identification of molecular types of prostate cancer independent of PSMA.

Visualization of Intermetastatic Heterogeneity in Mixed Neuroendocrine Carcinoma-Acinar Adenocarcinoma of the Prostate by 68Ga-PSMA, 68Ga-FAPI, and 18F-FDG PET/CT

ABSTRACT

Mixed neuroendocrine carcinoma-acinar carcinoma is an uncommon histological type of neuroendocrine prostate cancer. It has been rarely reported in de novo prostate malignancies. In this case, we present 68Ga-PSMA (prostate-specific membrane antigen), 68Ga-FAPI, and 18F-FDG PET/CT findings in the de novo form of mixed large-cell neuroendocrine carcinoma-acinar adenocarcinoma of the prostate. Different levels of radiotracer uptake were observed in different metastatic sites on 68Ga-PSMA, 68Ga-FAPI, and 18F-FDG PET/CT. This case demonstrates that the multitracer PET/CT strategy may be used for the noninvasive detection of the intermetastatic heterogeneity in metastatic neuroendocrine prostate cancer.

Expression of high molecular weight cytokeratin-A novel feature of aggressive and innate hormone-refractory prostatic adenocarcinoma

BACKGROUND

Castration-resistance is common in advanced prostatic adenocarcinomas (PACs) treated with androgen deprivation therapy (ADT) and usually occurs after 2 years following treatment. A minority of PACs confer innate ADT resistance without prior hormonal treatment. The expression of HMWCK in PAC cells has not been studied. This study aimed to investigate the clinicopathologic and genomic features of HMWCK-expressing PACs and the relationship to ADT resistance.

METHODS

A total of 469 PACs were studied for HMWCK expression (39 postradiotherapy, 57 post-ADT, 373 treatment-naïve PACs). Clinicopathologic correlations of the HMWCK expression with tumor grade groups, specific tumor morphologies, tumor stages and disease recurrence/persistence/progression were performed. Five HMWCK⁺ PACs were also sequenced for genetic alterations.

RESULTS

Thirty one of the 469 cases (6.6%) showed variable HMWCK⁺ PAC. The HMWCK⁺ PAC often focally presented in the tumor and vast majority were associated with high Gleason scores and unfavorable growth patterns (cribriform, comedo-necrosis, and intraductal carcinoma) as well as high tumor stages. A small percentage of the HMWCK⁺ PCA (2/31, 6.5%) presented with frank squamous histomorphology. Vast majority (22/31, 87%) had no history of prior ADT. The HMWCK⁺ PAC all displayed diminished to lost expression of AR/NKX3.1. Most of the cases progressed within 12 months of ADT or disease persisted despite ADT. Of the 5 HMWCK⁺ PACs subjected to gene sequencing, 4 presented with PTEN/PI3K/MAPK pathway alterations.

CONCLUSION

The study demonstrated HMWCK⁺ PAC to be a novel type of innate ADT-resistant PAC. Overexpression of HMWCK in PAC can be potentially used as a surrogate biomarker for aggressive and innate hormone-refractory PACs. The genetic alterations imply potential therapeutic implications of PI3K/MAPK inhibitors in the treatment of these deadly diseases.

Primary Neuroendocrine Tumor of Prostate in a Case of Metastatic Adenocarcinoma of Lung: Rare Entity with Histopathological and Gallium 68 DOTANOC Positron Emission Tomography Correlation

Neuroendocrine tumor (NET) of the prostate is an extremely rare entity which represents <1% of the prostatic cancers, but with increasing incidence. Its spectrum encompasses several histological variants ranging from well-differentiated tumor which are often indolent in nature; to aggressive neuroendocrine carcinoma which portends aggressive management. Hence, such rare entities are to be characterized and treated accordingly. We report an unusual case of well-differentiated NET of prostate which was flagged on fluorodeoxyglucose positron emission tomography computed tomography (PET/CT) performed for other indication and confirmed on Gallium-68 DOTANOC PET/CT. Histopathology and immunohistochemistry confirmed the findings subsequently.

Reprint of: de novo neuroendocrine features in prostate cancer

Neuroendocrine tumors of the prostate are rare and encompass a group of entities that are classified based on a combination of morphological and immunohistochemical features. Despite the 2016 World Health Organization classification of prostatic neuroendocrine tumors, variants have been reported that do not fit well in the categorization scheme. While the majority of these tumors arise in the setting of castration-resistant prostate cancer (postandrogen deprivation therapy), de novo cases may occur. In this review, we highlight the most significant pathological and immunohistochemical features, emerging biomarkers, and molecular features of such tumors.

Imaging of neuroendocrine neoplasms of the male GU tract

Male genitourinary neuroendocrine neoplasms (GU-NENs) are rare, without any definite imaging characteristics. The WHO classified neuroendocrine neoplasms in the 2016 classification of the tumors of the urinary tract and genital organs along with other GU tumors; however, no pathologic grading system is available as published for gastroenteropancreatic neuroendocrine neoplasms. Often a multimodality approach using cross-sectional imaging techniques, such as molecular imaging and histopathology are implemented to arrive at the diagnosis. This article provides a review of the pathology and imaging features of the male GU-NENs.

Complexities of Prostate Cancer

Prostate cancer has a long disease history and a wide variety and uncertainty in individual patients' clinical progress. In recent years, we have seen a revolutionary advance in both prostate cancer patient care and in the research field. The power of deep sequencing has provided cistromic and transcriptomic knowledge of prostate cancer that has not discovered before. Our understanding of prostate cancer biology, from bedside and molecular imaging techniques, has also been greatly advanced. It is important that our current theragnostic schemes, including our diagnostic modalities, therapeutic responses, and the drugs available to target non-AR signaling should be improved. This review article discusses the current progress in the understanding of prostate cancer biology and the recent advances in diagnostic and therapeutic strategies.

Survival analysis of small cell carcinomas of the genitourinary system

Due to low incidence, there are no large prospective studies or clinical trials for small cell carcinoma (SCC) of the genitourinary system (GU), and most data are extrapolated from SCC of the lung. Using the SEER database, we analyzed incidence trends, overall survival, and cancer-specific survival using the log-rank test. Analysis of variables was performed using the Cox proportional hazards regression model. The analysis showed that SCC of the bladder and prostate were the most common types of GU SCC, with 1836 and 606 cases, respectively. In 2018, the incidence of SCC of the bladder and prostate was twice that of 2010 (P < 0.001). The overall survival and cancer-specific survival of patients with SCC of the bladder were significantly longer than those of patients with SCC of the prostate (P < 0.0001). SCC bladder patients with advanced age, more extensive growth, lymph node involvement, no surgical intervention, and the presence of the metastasis had worse survival outcomes (P < 0.05). The Asian/Pacific Islander race provided some survival benefits for patients with SCC of the bladder (P < 0.05). For patients with SCC of the prostate, only advanced age was a risk factor for poor outcomes (P < 0.05).

A rare case of prostate neuroendocrine tumor: A case report

Small cell prostate neuroendocrine carcinoma (SCPC) is a rare and highly aggressive malignant tumor. We present a case of a 52-year-old Iranian man, presenting with complaints of occasional gross hematuria and perineal pain for 6 months. PSA was 0.8 ng/ml. A digital rectal examination found a huge and hard prostate mass. He underwent a transrectal ultrasound-guided (TRUS) biopsy of the prostate. Histopathology showed high-grade small cell neuroendocrine carcinoma. Immunohistochemical markers were positive for synaptophysin with a Ki67 index of almost 100%. However, CD56 and chromogranin A markers were negative. Magnetic resonance imaging (MRI) of the prostate showed a prostate mass with invasion to the rectum, while contrast-enhanced computed tomography of the thorax, abdomen, and pelvis (CT TAP) ruled out metastasis. A multidisciplinary team discussion was carried out, and a decision was made for concurrent chemotherapy and radiation (cisplatin and etoposide for 4 cycles and 70 Gy, 35 fractions). There is a lack of consensus on the management of SCPC. The main modality of management in advanced (stage IV) disease is chemotherapy. It is a highly aggressive tumor with a poor prognosis and is not responsive to hormonal therapy.

Increased Density of Growth Differentiation Factor-15+ Immunoreactive M1/M2 Macrophages in Prostate Cancer of Different Gleason Scores Compared with Benign Prostate Hyperplasia

Simple Summary

Prostate cancer (PCa) is the second most diagnosed cancer and cause of death in men worldwide. The main challenge is to discover biomarkers for malignancy to guide the physician towards optimized diagnosis and therapy. There is recent evidence that growth differentiation factor-15 (GDF-15) is elevated in cancer patients. Therefore, we aimed to decipher GDF-15+ cell types and their density in biopsies of human PCa patients with Gleason score (GS)6–9 and benign prostate hyperplasia (BPH). Here we show that the density of GDF-15+ cells, mainly identified as interstitial macrophages (MΦ), was higher in GS6–9 than in BPH, and, thus, GDF-15 is intended to differentiate patients with high GS vs. BPH, as well as GS6 vs. GS7 (or even with higher malignancy). Some GDF-15+ MΦ showed a transepithelial migration into the glandular lumen and, thus, might be used for measurement in urine/semen. Taken together, GDF-15 is proposed as a novel tool to diagnose PCa vs. BPH or malignancy (GS6 vs. higher GS) and as a potential target for anti-tumor therapy. GDF-15 in seminal plasma and/or urine could be utilized as a non-invasive biomarker of PCa as compared to BPH.

Abstract

Although growth differentiation factor-15 (GDF-15) is highly expressed in PCa, its role in the development and progression of PCa is unclear. The present study aims to determine the density of GDF-15+ cells and immune cells (M1-/M2 macrophages [MΦ], lymphocytes) in PCa of different Gleason scores (GS) compared to BPH. Immunohistochemistry and double immunofluorescence were performed on paraffin-embedded human PCa and BPH biopsies with antibodies directed against GDF-15, CD68 (M1 MΦ), CD163 (M2 MΦ), CD4, CD8, CD19 (T /B lymphocytes), or PD-L1. PGP9.5 served as a marker for innervation and neuroendocrine cells. GDF-15+ cell density was higher in all GS than in BPH. CD68+ MΦ density in GS9 and CD163+ MΦ exceeded that in BPH. GDF-15+ cell density correlated significantly positively with CD68+ or CD163+ MΦ density in extratumoral areas. Double immunoreactive GDF-15+/CD68+ cells were found as transepithelial migrating MΦ. Stromal CD68+ MΦ lacked GDF-15+. The area of PGP9.5+ innervation was higher in GS9 than in BPH. PGP9.5+ cells, occasionally copositive for GDF-15+, also occurred in the glandular epithelium. In GS6, but not in BPH, GDF-15+, PD-L1+, and CD68+ cells were found in epithelium within luminal excrescences. The degree of extra-/intra-tumoral GDF-15 increases in M1/M2Φ is proposed to be useful to stratify progredient malignancy of PCa. GDF-15 is a potential target for anti-tumor therapy.

De Novo Neuroendocrine Features in Prostate Cancer

Neuroendocrine tumors of the prostate are rare and encompass a group of entities that are classified based on a combination of morphological and immunohistochemical features. Despite the 2016 World Health Organization classification of prostatic neuroendocrine tumors, variants have been reported that do not fit well in the categorization scheme. While the majority of these tumors arise in the setting of castration-resistant prostate cancer (postandrogen deprivation therapy), de novo cases may occur. In this review, we highlight the most significant pathological and immunohistochemical features, emerging biomarkers, and molecular features of such tumors.

Single-cell transcriptional regulation and genetic evolution of neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer, with a 10% five-year survival rate. However, little is known about its origin and the mechanisms governing its emergence. Our study characterized ADPC and NEPC in prostate tumors from 7 patients using scRNA-seq. First, we identified two NEPC gene expression signatures representing different phases of trans-differentiation. New marker genes we identified may be used for clinical diagnosis. Second, integrative analyses combining expression and subclonal architecture revealed different paths by which NEPC diverges from the original ADPC, either directly from treatment-naïve tumor cells or from specific intermediate states of treatment-resistance. Third, we inferred a hierarchical transcription factor (TF) network underlying the progression, which involves constitutive regulation by ASCL1, FOXA2, and selective regulation by NKX2-2, POU3F2, and SOX2. Together, these results defined the complex expression profiles and advanced our understanding of the genetic and transcriptomic mechanisms leading to NEPC differentiation.

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Single-cell RNA sequencing revealed two distinct transcriptional programs of NEPC

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Cell-level clonal evolution analysis extended the divergent model of ADPC to NEPC

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Screening of NEPC-specific transcription factors through network-based approaches

Neuroendocrine Differentiation in the Setting of Prostatic Carcinoma: Contemporary Assessment of a Consecutive Series

AIM

Clinicopathologic characterization of contemporary series of neuroendocrine (NE) differentiation in the setting of prostatic carcinoma (PCa).

METHODS & RESULTS

We reviewed institutional databases for in-house cases with history of PCa and histopathologic evidence of NE differentiation during the disease course. 79 cases identified: 32 primary and 47 metastases. Metastatic lesions were in liver [n=15], lymph node [n=9], bone [n=6], lung [n=3], brain [n=1], other sites [n=13]. 63 of 76 (82%) cases with NE differentiation and available history were post-therapy: 6 post-radiation therapy (RT), 24 post- androgen-deprivation therapy (ADT) and 33 post-RT+ADT. Morphologic assessment [n=79]: a. 23 pure small cell/high-grade NE carcinoma (HGNEC): 20/23 metastatic; b. 10 combined high-grade PCa and small cell/HGNEC: 9/10 primary; c. 15 PCa with diffuse NE immunohistochemistry (IHC) marker positivity/differentiation, associated with nested to sheet-like growth of cells with abundant cytoplasm and prominent nucleoli, yet diffuse positivity for at least one prostatic and one NE IHC marker: all metastatic; d. 11 PCa with patchy NE differentiation, displaying more than single cell positivity for NE IHC: 5 primary / 6 metastatic; e. 9 PCa with focal NE marker positive cells: 4 primary / 5 metastatic; f. 11 PCa with 'Paneth cell-like' change: all primary.

CONCLUSIONS

In this contemporary series, the majority of NE differentiation in the setting of PCa was seen post-therapy. We highlight tendencies of small cell/HGNEC and PCa with diffuse NE differentiation by IHC to occur in metastatic settings, while morphologically combined high grade PCa+small cell/HGNEC and 'Paneth cell-like' change occur in primary disease.

Primary Prostatic Carcinoma With De Novo Diffuse Neuroendocrine Differentiation

The 2016 World Health Organization classification of prostate cancer with neuroendocrine (NE) differentiation includes NE cells in usual prostate cancer, adenocarcinoma with Paneth cell-like NE differentiation, well-differentiated NE tumor (carcinoid), small cell NE carcinoma, and large cell NE carcinoma. In this article, we report a rare case of primary prostatic carcinoma with de novo diffuse NE differentiation presenting with bilateral hydronephrosis in a 79-year-old man. This case did not fit into any of the existing classifications. The clinical, radiological, morphological, and immunohistochemical findings and response to androgen deprivation therapy (ADT) are presented. The proposed pathogenesis of NE differentiation via transdifferentiation from conventional prostatic adenocarcinoma whereby genomic alterations, coupled with ADT can induce lineage plasticity resulting in NE differentiation is described.

Patterns of indolence in prostate cancer (Review)

Although prostate cancer is a major cause of cancer-related mortality worldwide, most patients will have a relatively indolent clinical course. Contrary to most other types of cancer, even the diagnosis of locally advanced or metastatic disease is not always lethal. The present review aimed to summarize what is known regarding the underlying mechanisms related to the indolent course of subsets of prostate cancer, at various stages. The data suggested that no specific gene alteration by itself was responsible for carcinogenesis or disease aggressiveness. However, pathway analysis identified genetic aberrations in multiple critical pathways that tend to accumulate over the course of the disease. The progression from indolence into aggressive disease is associated with a complex interplay in which genetic and epigenetic factors are involved. The effect of the immune tumor microenvironment is also very important. Emerging evidence has suggested that the upregulation of pathways related to cellular aging and senescence can identify patients with indolent disease. In addition, a number of tumors enter a long-lasting quiescent state. Further research will determine whether halting tumor evolution is a feasible option, and whether the life of patients can be markedly prolonged by inducing tumor senescence or long-term dormancy.

Small cell-like change in prostatic adenocarcinoma and intraductallesions – neuroendocrine or not?

Background

Small cell-like change in prostatic neoplasia (both invasive adenocarcinoma and intraepithelial lesions) is described in three previous reports. None of them to date proved to be associated with overt prostate neuroendocrine carcinoma.

Case presentation

We report findings from a radical prostatectomy of 80-year-old patient (adenocarcinoma GG5 pT3b with 10% involvement of the gland) with small cell-like change in intraductal carcinoma and in the invasive component. An additional 3.5-mm focus of poorly differentiated carcinoma was observed (PSA, TTF1, chromogranin and CD56 negative; synaptophysin positive in scattered cells; and a Ki67 label index of 50%).

Conclusion

Our case expands the data accumulated on small cell-like change in prostate neoplasia. As most of other reported cases, there was no expression of neuroendocrine markers or high proliferative index in small-cell like areas. On the other hand, for the first time, a transition morphology between acinar adenocarcinoma and neuroendocrine carcinoma was observed in a prostate with small cell-like change.

Aggressive variants of prostate cancer: underlying mechanisms of neuroendocrine transdifferentiation

Prostate cancer is a hormone-driven disease and its tumor cell growth highly relies on increased androgen receptor (AR) signaling. Therefore, targeted therapy directed against androgen synthesis or AR activation is broadly used and continually improved. However, a subset of patients eventually progresses to castration-resistant disease. To date, various mechanisms of resistance have been identified including the development of AR-independent aggressive variant prostate cancer based on neuroendocrine transdifferentiation (NED). Here, we review the highly complex processes contributing to NED. Genetic, epigenetic, transcriptional aberrations and posttranscriptional modifications are highlighted and the potential interplay of the different factors is discussed. Background Aggressive variant prostate cancer (AVPC) with traits of neuroendocrine differentiation emerges in a rising number of patients in recent years. Among others, advanced therapies targeting the androgen receptor axis have been considered causative for this development. Cell growth of AVPC often occurs completely independent of the androgen receptor signal transduction pathway and cells have mostly lost the typical cellular features of prostate adenocarcinoma. This complicates both diagnosis and treatment of this very aggressive disease. We believe that a deeper understanding of the complex molecular pathological mechanisms contributing to transdifferentiation will help to improve diagnostic procedures and develop effective treatment strategies. Indeed, in recent years, many scientists have made important contributions to unravel possible causes and mechanisms in the context of neuroendocrine transdifferentiation. However, the complexity of the diverse molecular pathways has not been captured completely, yet. This narrative review comprehensively highlights the individual steps of neuroendocrine transdifferentiation and makes an important contribution in bringing together the results found so far.

Prostate Pathology: What is New in the 2022 WHO Classification of Urinary and Male Genital Tumors?

In 2022, after a six-year interval, the International Agency for Research on Cancer (IARC) has published the 5th edition of the WHO Classification of Urinary and Male Genital Tumors, which provides a comprehensive update on tumor classification of the genitourinary system. This review article focuses on prostate carcinoma and underscores changes in the prostate chapter as well as those made across the entire series of the 5th edition of WHO Blue Books. Although no major alterations were made to this chapter, some of the most notable updates include restructure of contents and introduction of a new format; standardization of mitotic counts, genomic nomenclatures, and units of length; refined definition for the terms "variant", "subtype", and "histologic pattern"; reclassification of prostatic intraepithelial neoplasia (PIN)-like adenocarcinoma as a subtype of prostatic acinar adenocarcinoma; and recognition of treatment-related neuroendocrine prostatic carcinoma as a distinct tumor type. Evolving and unsettled issues related to grading of intraductal carcinoma of the prostate and reporting of tertiary Gleason pattern, the definition and prognostic significance of cribriform growth pattern, and molecular pathology of prostate cancer will also be covered in this review.

Endocrine and paracrine characteristics of neuroendocrine prostate cancer

Prostate cancer is a common malignancy affecting men worldwide. While the vast majority of newly diagnosed prostate cancers are categorized as adenocarcinomas, a spectrum of uncommon tumor types occur including those with small cell and neuroendocrine cell features. Benign neuroendocrine cells exist in the normal prostate microenvironment, and these cells may give rise to primary neuroendocrine carcinomas. However, the more common development of neuroendocrine prostate cancer is observed after therapeutics designed to repress the signaling program regulated by the androgen receptor which is active in the majority of localized and metastatic adenocarcinomas. Neuroendocrine tumors are identified through immunohistochemical staining for common markers including chromogranin A/B, synaptophysin and neuron specific enolase (NSE). These markers are also common to neuroendocrine tumors that arise in other tissues and organs such as the gastrointestinal tract, pancreas, lung and skin. Notably, neuroendocrine prostate cancer shares biochemical features with nerve cells, particularly functions involving the secretion of a variety of peptides and proteins. These secreted factors have the potential to exert local paracrine effects, and distant endocrine effects that may modulate tumor progression, invasion, and resistance to therapy. This review discusses the spectrum of factors derived from neuroendocrine prostate cancers and their potential to influence the pathophysiology of localized and metastatic prostate cancer.

Imaging of Neuroendocrine Prostatic Carcinoma

Neuroendocrine prostate cancer (NEPC) is an aggressive subtype of prostate cancer that typically has a high metastatic potential and poor prognosis in comparison to the adenocarcinoma subtype. Although it can arise de novo, NEPC much more commonly occurs as a mechanism of treatment resistance during therapy for conventional prostatic adenocarcinoma, the latter is also termed as castration-resistant prostate cancer (CRPC). The incidence of NEPC increases after hormonal therapy and they represent a challenge, both in the radiological and pathological diagnosis, as well as in the clinical management. This article provides a comprehensive imaging review of prostatic neuroendocrine tumors.

Neuroendocrine cells in prostate cancer correlate with poor outcomes: a systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis of the literature to understand the variation in the reporting of neuroendocrine staining and determine the influence of reporting neuroendocrine staining at diagnosis on patient outcomes.

METHODS

Medical databases were searched to identify studies in which adenocarcinoma specimens were stained with any of the following four neuroendocrine markers: chromogranin A (CgA), neuron-specific enolase (NSE), synaptophysin and CD56. The prevalence of neuroendocrine staining and correlation of the prevalence of neuroendocrine staining to patient outcomes were analysed using a random-effects model. All statistical tests were two-sided.

RESULTS

Sixty-two studies spanning 7616 patients were analysed. The pooled prevalence for the most common marker, CgA (41%), was similar to that of NSE (39%) and higher than that of synaptophysin (31%). The prevalence of CgA staining was significantly influenced by reporting criteria, where objective thresholds reduced the variation in prevalence to 26%. No correlation was found between CgA prevalence and tumour grade. Patients positive for CgA staining using objective criteria had more rapid biochemical progression (hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.49 to 2.65) and poorer prostate cancer-specific survival (HR 7.03, 95% CI 2.55 to 19.39) compared to negative patients, even among those with low-risk cancers.

CONCLUSION

Discrepancies in the reported prevalence of neuroendocrine cells in adenocarcinoma are driven by the inconsistent scoring criteria. This study unequivocally demonstrates that when neuroendocrine cell staining is assessed with objective criteria it identifies patients with poor clinical outcomes. Future studies are needed to determine the exact quantifiable thresholds for use in reporting neuroendocrine cell staining to identify patients at higher risk of progression.

[Localized prostate cancer]

Prostate cancer is the most prevalent noncutaneous cancer in men. The Gleason grading is considered to be the strongest prognostic parameter regarding progression-free survival and overall survival. The original grading system has been modified during the last decade resulting in a more precise prognostic tool. The pretreatment Gleason score guides clinical management and is a key component in S3 guidelines for prostate cancer. In addition to Gleason score several other histologic findings in prostate needle biopsy influence patient management. In this second part of our CME series about prostate cancer, we will discuss the diagnosis of prostate cancer and current guidelines for reporting prostate cancer. In addition, we will highlight prostate lesions of urothelial origin and neuroendocrine prostate cancer as well as prognostic biomarkers.

Role of PI3K-AKT-mTOR Pathway as a Pro-Survival Signaling and Resistance-Mediating Mechanism to Therapy of Prostate Cancer

Androgen deprivation therapy (ADT) and androgen receptor (AR)-targeted therapy are the gold standard options for treating prostate cancer (PCa). These are initially effective, as localized and the early stage of metastatic disease are androgen- and castration-sensitive. The tumor strongly relies on systemic/circulating androgens for activating AR signaling to stimulate growth and progression. However, after a certain point, the tumor will eventually develop a resistant stage, where ADT and AR antagonists are no longer effective. Mechanistically, it seems that the tumor becomes more aggressive through adaptive responses, relies more on alternative activated pathways, and is less dependent on AR signaling. This includes hyperactivation of PI3K-AKT-mTOR pathway, which is a central signal that regulates cell pro-survival/anti-apoptotic pathways, thus, compensating the blockade of AR signaling. The PI3K-AKT-mTOR pathway is well-documented for its crosstalk between genomic and non-genomic AR signaling, as well as other signaling cascades. Such a reciprocal feedback loop makes it more complicated to target individual factor/signaling for treating PCa. Here, we highlight the role of PI3K-AKT-mTOR signaling as a resistance mechanism for PCa therapy and illustrate the transition of prostate tumor from AR signaling-dependent to PI3K-AKT-mTOR pathway-dependent. Moreover, therapeutic strategies with inhibitors targeting the PI3K-AKT-mTOR signal used in clinic and ongoing clinical trials are discussed.

ZNF507 affects TGF-β signaling via TGFBR1 and MAP3K8 activation in the progression of prostate cancer to an aggressive state

Background

The progression of prostate cancer (PC) to the highly aggressive metastatic castration-resistant prostate cancer (mCRPC) or neuroendocrine prostate cancer (NEPC) is a fatal condition and the underlying molecular mechanisms are poorly understood. Here, we identified the novel transcriptional factor ZNF507 as a key mediator in the progression of PC to an aggressive state.

Methods

We analyzed ZNF507 expression in the data from various human PC database and high-grade PC patient samples. By establishment of ZNF507 knockdown and overexpression human PC cell lines, we assessed in vitro PC phenotype changes including cell proliferation, survival, migration and invasion. By performing microarray with ZNF507 knockdown PC cells, we profiled the gene clusters affected by ZNF507 knockdown. Moreover, ZNF507 regulated key signal was evaluated by dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays. Finally, we performed xenograft and in vivo metastasis assay to confirm the effect of ZNF507 knockdown in PC cells.

Results

We found that ZNF507 expression was increased, particularly in the highly graded PC. ZNF507 was also found to be associated with metastatic PC of a high grade. Loss- or gain-of-function–based analysis revealed that ZNF507 promotes the growth, survival, proliferation, and metastatic properties of PC (e.g., epithelial-mesenchymal transition) by upregulating TGF-β signaling. Profiling of gene clusters affected by ZNF507 knockdown revealed that ZNF507 positively regulated the transcription of TGFBR1, MAP3K8, and FURIN, which in turn promoted the progression of PC to highly metastatic and aggressive state.

Conclusions

Our findings suggest that ZNF507 is a novel key regulator of TGF-β signaling in the progression of malignant PC and could be a promising target for studying the development of advanced metastatic PCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02094-3.

Dietary tomato inhibits angiogenesis in TRAMP prostate cancer but is not protective with a Western-style diet in this pilot study

Prostate cancer (PCa) remains the second most diagnosed cancer worldwide. Higher body weight is associated with chronic inflammation, increased angiogenesis, and treatment-resistant tumor phenotypes. Dietary tomato reduces PCa risk, which may be due to tomato inhibition of angiogenesis and disruption of androgen signaling. This pilot study investigated the interplay between tomato powder (TP), incorporated into control (CON) and obesogenic (OB) diets, and PCa tumor growth and blood perfusion over time in a transgenic model of PCa (TRAMP). Ultrasound microvessel imaging (UMI) results showed good agreement with gold-standard immunohistochemistry quantification of endothelial cell density, indicating that this technique can be applied to non-invasively monitor tumor blood perfusion in vivo. Greater body weight was positively associated with tumor growth. We also found that TP significantly inhibited prostate tumor angiogenesis but that this inhibition differentially affected measured outcomes depending on CON or OB diets. TP led to reduced tumor growth, intratumoral inflammation, and intratumoral androgen-regulated gene expression (srd5a1, srd5a2) when incorporated with the CON diet but greater tumor growth and intratumoral gene expression when incorporated with the OB diet. Results from this study show that protective benefits from dietary tomato are lost, or may become deleterious, when combined with a Western-style diet.

Chromatin-directed proteomics-identified network of endogenous androgen receptor in prostate cancer cells

Treatment of prostate cancer confronts resistance to androgen receptor (AR)-targeted therapies. AR-associated coregulators and chromatin proteins hold a great potential for novel therapy targets. Here, we employed a powerful chromatin-directed proteomics approach termed ChIP-SICAP to uncover the composition of chromatin protein network, the chromatome, around endogenous AR in castration resistant prostate cancer (CRPC) cells. In addition to several expected AR coregulators, the chromatome contained many nuclear proteins not previously associated with the AR. In the context of androgen signaling in CRPC cells, we further investigated the role of a known AR-associated protein, a chromatin remodeler SMARCA4 and that of SIM2, a transcription factor without a previous association with AR. To understand their role in chromatin accessibility and AR target gene expression, we integrated data from ChIP-seq, RNA-seq, ATAC-seq and functional experiments. Despite the wide co-occurrence of SMARCA4 and AR on chromatin, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, especially those involved in cell morphogenetic changes in epithelial-mesenchymal transition. The depletion also inhibited the CRPC cell growth, validating SMARCA4's functional role in CRPC cells. Although silencing of SIM2 reduced chromatin accessibility similarly, it affected the expression of a much larger group of androgen-regulated genes, including those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of CRPC cells and tumor size in chick embryo chorioallantoic membrane assay, further emphasizing the importance of SIM2 in CRPC cells and pointing to the functional relevance of this potential prostate cancer biomarker in CRPC cells. Overall, the chromatome of AR identified in this work is an important resource for the field focusing on this important drug target.

A 25 year perspective on advances in the pathologic assessment and diagnosis of urologic cancers

Over the past 25 years, diagnostic categories in genitourinary pathology have changed dramatically. Prostate cancer reporting incorporated numerous new variant categories, recognized the importance of intraductal carcinoma, and introduced the concept of Grade Groups. Pathologic diagnosis of bladder cancer not only added new variant categories, but also modified the grading of non-invasive urothelial neoplasms and refined staging definitions. Kidney cancer classification expanded from a handful of diagnostic categories to a broad array of additional cancer types defined by unique immunohistochemical and molecular findings. Segregation of penile carcinoma by human papillomavirus status more accurately reflected pathogenesis and helped improve prediction of cancer behavior. Testicular pathology research advanced understanding of germ cell tumor subtypes and their impact on patient outcomes. Finally, adrenal gland pathology has evolved to incorporate a broader recognition of morphological variation and risk factors associated with tumor progression. Taken together, changes in pathology over the past quarter century have revolutionized our approach to genitourinary cancers. This review seeks to highlight some of the many significant changes in genitourinary pathology that have occurred during the past 25 years and emphasize impacts on clinical outcomes or therapy, as relevant.