De Novo Neuroendocrine Features in Prostate Cancer

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.

Rapidly Progressing Prostate Cancer With Low Prostate-Specific Antigen and Gleason Score 5+5: A Case Report

An 87-year-old man presented with worsening urinary dysfunction with urinary retention. The prostate-specific antigen was 1.23 ng/mL. Prostate biopsy confirmed adenocarcinoma with a Gleason score of 5+5; the final diagnosis was T4N1M0. Androgen deprivation therapy and immediate whole-pelvic radiotherapy (80 Gy) were administered. Nadir prostate-specific antigen of 0.40 ng/mL two months later increased to 35.92 ng/mL as the disease metastasized to the corpus cavernosum penis, causing malignant priapism. The best supportive care was provided, and the patient died 11 months later. High-grade prostate cancers with low prostate-specific antigen levels are rare but highly aggressive. Androgen deprivation therapy and radiotherapy alone may be insufficient in such cases, highlighting the need for more effective treatment strategies.

Molecular Landscape of Aggressive Histologic Subtypes of Localized Prostate Cancer

Despite incredible progress in describing the molecular underpinnings of prostate cancer over the last decades, pathologic examination remains indispensable for predicting aggressive behavior in the localized setting. Beyond pathologic grade, specific histologic findings have emerged as critical prognostic or predictive indicators. Here, the authors review molecular correlates of aggressive histologic subtypes of prostate cancer in the localized setting, demonstrating that many of the signature molecular alterations found in metastatic disease-such as tumor suppressor gene loss and DNA repair defects-are enriched in primary disease with adverse histologic features, presaging aggressive behavior, and presenting opportunities for earlier germline screening or targeted therapies.

Framework for the Pathology Workup of Metastatic Castration-Resistant Prostate Cancer Biopsies

Lineage plasticity and histologic transformation from prostate adenocarcinoma to neuroendocrine (NE) prostate cancer (NEPC) occur in up to 15% to 20% of patients with castration-resistant prostate cancer (CRPC) as a mechanism of treatment resistance and are associated with aggressive disease and poor prognosis. NEPC tumors typically display small cell carcinoma morphology with loss of androgen receptor (AR) expression and gain of NE lineage markers. However, there is a spectrum of phenotypes that are observed during the lineage plasticity process, and the clinical significance of mixed histologies or those that co-express AR and NE markers or lack all markers is not well defined. Translational research studies investigating NEPC have used variable definitions, making clinical trial design challenging. In this manuscript, we discuss the diagnostic workup of metastatic biopsies to help guide the reproducible classification of phenotypic CRPC subtypes. We recommend classifying CRPC tumors based on histomorphology (adenocarcinoma, small cell carcinoma, poorly differentiated carcinoma, other morphologic variant, or mixed morphology) and IHC markers with a priority for AR, NK3 homeobox 1, insulinoma-associated protein 1, synaptophysin, and cell proliferation based on Ki-67 positivity, with additional markers to be considered based on the clinical context. Ultimately, a unified workup of metastatic CRPC biopsies can improve clinical trial design and eventually practice.

Real-world Clinical Outcomes and Prognostic Factors in Neuroendocrine Prostate Cancer

BACKGROUND

Neuroendocrine prostate cancer (NEPC) encompasses pure NEPC and tumors with mixed adenocarcinoma and neuroendocrine histology. While NEPC is thought to confer a poor prognosis, outcome data are sparse, making risk stratification and treatment decisions difficult for clinicians.

METHODS

This retrospective study identified patients with morphological and/or immunohistochemical NEPC features on pathological review of high-grade prostate cancer cases. Median overall survival (OS) was calculated by stage and castration sensitivity. Prognostic factors were assessed via multivariate analysis. OS and progression-free survival on first-line metastatic systemic treatment were also evaluated.

RESULTS

Of 135 NEPC cases, 25.9% had NEPC documented in the original pathological report. Mixed pathology was found in 91.9% of cases. Median OS from NEPC diagnosis was 59.2, 42.3, 14.3, 17.6 and 9.6 months for localized, nonmetastatic castration-sensitive, nonmetastatic castration-resistant, metastatic castration-sensitive and metastatic castration-resistant prostate cancer, respectively. Anemia (hazard ratio [HR]: 1.66; 95% CI 1.05-2.16; P = .031) and elevated neutrophil-lymphocyte ratio (NLR) (HR: 1.51; 95% CI 1.01-2.52; P = .045), were associated with increased risk of death on multivariate analysis. 67 patients received first-line metastatic treatment beyond androgen deprivation, with a median progression-free survival of 5.2 months and OS of 15 months. Of these, 50.7% received more than 1 line of systemic treatment.

CONCLUSION

We observed underdiagnosis of NEPC in pathology specimens. NEPC is associated with poorer prognosis than would be expected in pure adenocarcinoma populations, with rapid progression on first-line metastatic treatment and sharp drop-off between subsequent treatment lines. Anemia and elevated NLR were associated with poor survival.

Structural Optimization of Isoquinoline Derivatives from Lycobetaine and Their Inhibitory Activity against Neuroendocrine Prostate Cancer Cells

Neuroendocrine prostate cancer (NEPC) is a highly aggressive cancer that is resistant to hormone therapy and characterized by poor prognosis, as well as limited therapeutic options. Since the natural product lycobetaine was reported to exhibit good antitumor activities against various types of cancers, we initially simplified the scaffold of lycobetaine to obtain the active compound 1, an isoquinoline derivative with an aryl moiety substitution at the 4-position, which showed apparent antiproliferative activities against NPEC cell line LASCPC-01 in vitro. Subsequently, we carried out structural optimization and systematic structure-activity relationship (SAR) studies on compound 1, leading to the discovery of compound 46, which demonstrated potent inhibitory activities against the LASCPC-01 cell line with an IC50 value of 0.47 μM. Moreover, compound 46 displayed remarkable selectivity over prostate cancer cell line PC-3 with a selectivity index greater than 190-fold. Further cell-based mechanism studies revealed that compound 46 and lycobetaine can effectively induce G1 cell cycle arrest and apoptosis dose dependently. However, lycobetaine inhibited the expression of neuroendocrine markers, while compound 46 slightly upregulated these proteins. This suggested that compound 46 might exert its antitumor activities through a different mechanism than lycobetaine, warranting further study.

Quadruplet Therapy in De Novo High-Volume Mixed Neuroendocrine Prostate Cancer Using 177Lu-PSMA: A Case Report

ABSTRACT

We present a case of de novo high-volume metastatic prostate cancer with high PSMA expression, partially PSMA-negative, using quadruplet therapy (PROMISE ver. 2 miTNM; miT4N2M1aM1b(dmi) PRIMARY score: 5, PSMA-expression score: 0-3). Because of our patient's partial PSMA negativity and after a multidisciplinary tumor board discussion, we decided to use a modified protocol involving doublet hormonal therapy along with 177Lu-PSMA and radiation therapy to address the PSMA-negative disease. The patient responded well to this treatment, but recurrence was ultimately inevitable. This case represents a typical example of mixed neuroendocrine prostate carcinoma and highlights its resistant phenotype in response to quadruplet therapy.

SkinLesNet: Classification of Skin Lesions and Detection of Melanoma Cancer Using a Novel Multi-Layer Deep Convolutional Neural Network

Skin cancer is a widespread disease that typically develops on the skin due to frequent exposure to sunlight. Although cancer can appear on any part of the human body, skin cancer accounts for a significant proportion of all new cancer diagnoses worldwide. There are substantial obstacles to the precise diagnosis and classification of skin lesions because of morphological variety and indistinguishable characteristics across skin malignancies. Recently, deep learning models have been used in the field of image-based skin-lesion diagnosis and have demonstrated diagnostic efficiency on par with that of dermatologists. To increase classification efficiency and accuracy for skin lesions, a cutting-edge multi-layer deep convolutional neural network termed SkinLesNet was built in this study. The dataset used in this study was extracted from the PAD-UFES-20 dataset and was augmented. The PAD-UFES-20-Modified dataset includes three common forms of skin lesions: seborrheic keratosis, nevus, and melanoma. To comprehensively assess SkinLesNet's performance, its evaluation was expanded beyond the PAD-UFES-20-Modified dataset. Two additional datasets, HAM10000 and ISIC2017, were included, and SkinLesNet was compared to the widely used ResNet50 and VGG16 models. This broader evaluation confirmed SkinLesNet's effectiveness, as it consistently outperformed both benchmarks across all datasets.

Immunoreactivity of HOXB13 in Neuroendocrine Neoplasms Is a Sensitive and Specific Marker of Rectal Well-Differentiated Neuroendocrine Tumors

HoxB13 is a transcription factor involved in defining of posterior endodermal derivatives, including prostate and rectum. While it is used as a marker of prostatic adenocarcinoma, it has not been studied systematically in neuroendocrine neoplasms. Thus, we performed HoxB13 immunohistochemistry in tissue microarrays and the whole sections of 232 neuroendocrine neoplasms. These included 34 paragangliomas (PGs), 20 cauda equina neuroendocrine tumors (CENETs), 123 well-differentiated neuroendocrine tumors (WDNETs), and 55 neuroendocrine carcinomas (NECs). WDNETs were additionally analyzed with SATB2, and colorectal WDNETs with CDX2 and serotonin immunohistochemistry. In total, HoxB13 immunoreactivity was observed in 95% (19/20) CENETs, 10.6% (13/123) WDNETs, and 12.9% (7/54) NECs. No PGs were positive. Large intestine WDNETs expressed HoxB13 in 68.4% (13/19); five negative tumors originated in cecum and one in rectum. In rectum, 92.9% (13/14) WDNETs expressed HoxB13. HoxB13 was 92.9% sensitive and 100% specific, showing 100% positive predictive value for the rectal origin of WDNET. In NECs, HoxB13 was positive in 15.4% (2/13) GIT tumors and 80% (4/5) prostatic NECs, but in none of urinary bladder NECs (0/8). SATB2 was positive in 17.1% (21/123) WDNETs, including 78.9% (15/19) of colorectal WDNETs, 71.4% (5/7) appendiceal WDNETs, and 2.9% (1/34) small intestine WDNETs. All 4 SATB2-negative large bowel tumors originated in the cecum. When both markers combined, HoxB13+/SATB2+ immunoprofile was seen exclusively in rectal WDNETs (positive predictive value 100%), while HoxB13-/SATB2+ immunoprofile was highly suggestive of the appendiceal origin (positive predictive value 71.4%). Therefore, HoxB13 can be useful as an immunohistochemical marker of rectal WDNETs and prostatic NECs.

Genomic Evolution and Transcriptional Changes in the Evolution of Prostate Cancer into Neuroendocrine and Ductal Carcinoma Types

Prostate cancer is typically of acinar adenocarcinoma type but can occasionally present as neuroendocrine and/or ductal type carcinoma. These are associated with clinically aggressive disease, and the former often arises on a background of androgen deprivation therapy, although it can also arise de novo. Two prostate cancer cases were sequenced by exome capture from archival tissue. Case 1 was de novo small cell neuroendocrine carcinoma and ductal adenocarcinoma with three longitudinal samples over 5 years. Case 2 was a single time point after the development of treatment-related neuroendocrine prostate carcinoma. Case 1 showed whole genome doubling in all samples and focal amplification of AR in all samples except the first time point. Phylogenetic analysis revealed a common ancestry for ductal and small cell carcinoma. Case 2 showed 13q loss (involving RB1) in both adenocarcinoma and small cell carcinoma regions, and 3p gain, 4p loss, and 17p loss (involving TP53) in the latter. By using highly curated samples, we demonstrate for the first time that small-cell neuroendocrine and ductal prostatic carcinoma can have a common ancestry. We highlight whole genome doubling in a patient with prostate cancer relapse, reinforcing its poor prognostic nature.

Metastatic prostate cancer diagnosed by fine-needle aspiration: Contemporary cytopathologic and biomarker assessment with clinical correlates

INTRODUCTION

The diagnosis of metastatic prostatic cancer (MPC) by fine needle aspiration (FNA) can usually be rendered by typical cytomorphologic and immunohistochemical (IHC) features. However, MPC diagnosis may be complicated by transformation to atypical phenotypes such as small cell carcinoma, typically under pressure from androgen deprivation therapy (ADT). Predictive and prognostic biomarkers can also be assessed by IHC. This study illustrates how careful assessment of cytologic and biomarker features may provide therapeutic and prognostic information in MPC.

DESIGN

We reviewed our anatomic pathology archives for MPC diagnosed by FNA from January 2014 to June 2021. Clinical histories, cytology slides, and cell blocks were reviewed. Extensive IHC biomarker workup was performed, including markers of prostate lineage, cell-cycle dysfunction, Ki-67, neuroendocrine markers, PDL1, and androgen receptor splice variant 7. Cases were reclassified into three categories: conventional type, intermediary type, and high-grade neuroendocrine carcinoma (HGNC).

RESULTS

Eighteen patients were identified. Twelve had conventional MPC, including six of six ADT-naive patients. Six of twelve (50%) with prior ADT were reclassified as intermediary or HGNC. Four intermediary cases included two with squamous differentiation and two with pro-proliferative features. Two HGNC cases had typical small cell carcinoma cytomorphology. Expression of PDL1 was identified in two cases and ARv7 in three cases. Five of five intermediary and HGNC patients died of disease versus six of eleven with with conventional type.

CONCLUSIONS

Aggressive cytomorphologic variants were commonly identified in patients with prior ADT. Identification of nonconventional cytomorphology and increased proliferation can provide important prognostic information. Recognition of these changes is important for an accurate diagnosis, and the identification of high-grade variants can affect therapeutic decision-making. Clinically actionable biomarkers such as PDL1 and ARv7 can be assessed by IHC.

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.