Progression of prostate cancer to neuroendocrine cell tumor

Impact of Angiotensin Converting Enzyme Inhibitors on Pathologic Complete Response With Neoadjuvant Chemotherapy for Muscle Invasive Bladder Cancer

INTRODUCTION

The renin-angiotensin system (RAS) has been demonstrated to modulate cell proliferation, desmoplasia, angiogenesis and immunosuppression. We examined the association of RAS inhibitors (RASi)-namely angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB)-with neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) preceding radical cystectomy (RC).

PATIENTS AND METHODS

We retrospectively investigated concurrent RASi use with NAC prior to RC in 302 patients with MIBC from 3 academic institutions. Outcomes included pathologic complete response (pCR) and overall survival (OS). Pathologic features, performance status (PS), clinical stage, type/number of cycles of NAC, and toxicities were collected.

RESULTS

Overall pCR rate was 26.2% and 5-year OS was 62%. Concurrent ACEi intake with NAC approached significance for association with pCR (odds ratio [OR] = 1.71; 95% CI, 0.94-3.11; P = .077). Patients with cT3/4N0-N1 disease receiving ACEi had higher pCR rates (30.8% vs. 17.7%, P = .056) than those not on ACEi. Female sex had a statistically significant favorable interaction for pCR with ACEi intake (P = .044). ACEi intake was not associated with OS, while pCR, PS and lower clinical stage were significantly associated with improved OS.

CONCLUSION

ACEi intake is potentially associated with increased pCR in patients with MIBC receiving NAC prior to RC, and this association is more pronounced in patients with higher clinical stage of disease at the initiation of therapy and female sex. Our data suggest the potential relevance of the RAS as a therapeutic target in aggressive MIBC.

Systemic metastases in large cell neuroendocrine prostate cancer: a rare case report and literature review

Neuroendocrine prostate neoplasms, encompassing small cell carcinoma, carcinoid, and large cell carcinoma, are infrequently observed in malignant prostate tumors. The occurrence of large cell neuroendocrine prostate cancer (LCNEPC) is exceedingly rare. In this study, the patient initially presented with a persistent dysuria for a duration of one year, accompanied by a serum prostate-specific antigen (PSA) level of 17.83ng/mL. Prostate magnetic resonance imaging (MRI) and chest computed tomography (CT) scan showed that a neoplastic lesion was considered, and prostate biopsy confirmed prostate adenocarcinoma with a Gleason score of 7 (4 + 3). Then, thoracoscopic lung tumor resection was performed, and the pathological examination revealed the presence of primary moderately differentiated invasive adenocarcinoma of the lung and metastatic prostate adenocarcinoma, the Gleason score was 8 (4 + 4). After 1 year of endocrine therapy with goserelin acetate and bicalutamide, he underwent a laparoscopic radical prostatectomy (LRP), the pathological report indicated the presence of adenocarcinoma mixed with NE carcinoma. Two months after the LRP, the patient experienced gross hematuria and sacral tail pain. Further examination revealed multiple metastatic lesions throughout the body. He also underwent transurethral resection of bladder tumor (TURBT) for bladder tumor and received etoposide+ cisplatin chemotherapy three weeks post-surgery. The patient eventually died of multi-organ failure due to myelosuppression after chemotherapy. This case report presents an uncommon instance of LCNEPC with widespread systemic metastases, while also providing a comprehensive review of existing literature to facilitate improved management and treatment strategies for similar patients in subsequent cases.

Urinary Neuroendocrine Neoplasms Treated in the "Modern Era": A Multicenter Retrospective Review

BACKGROUND

Primary urinary neuroendocrine neoplasms (U-NENs) are extremely rare thus optimal treatment is unknown. Grading and treatment are typically extrapolated from other primary sites. Since 2010, the clinical landscape for NENs has changed substantially. We performed a retrospective review of U-NENs to assess treatment patterns and oncologic outcomes of patients treated in the recent era of NEN therapy.

PATIENTS AND METHODS

A multicenter retrospective review of patients diagnosed after 2005 and alive after 2010. Time to treatment failure (TTF) was used to evaluate progression and toxicity for systemic therapy. Tumors were categorized as having either well-differentiated neuroendocrine tumor (WDNET) or poorly differentiated neuroendocrine carcinoma (PDNEC) histology.

RESULTS

A total of 134 patients from 6 centers were included in our analysis, including 94 (70%) bladder, 32 (24%) kidney, 2 (1.5%) urethra and 4 other urinary primaries (3.0%). Poorly-differentiated neuroendocrine carcinoma was more common in bladder (92%) than non-bladder tumors (8%). Median Ki-67 available in bladder primary was 90% (n = 24), kidney 10% (n = 23), ureter 95% (n = 1), urethra 54% (n = 2), and others 90% (n = 3). Patients received a median of 2 therapies (range 0-10). Median time to death was not reached in locoregional WDNETs versus 8.2 years (95% CI, 3.5-noncalculable) in metastatic WDNETs (predominantly renal primary). Median time to death was 3.6 years (95% CI, 2.2-9.2) in locoregional PDNECs versus 1 year (95% CI, 0.8-1.3) in metastatic PDNECs (predominantly bladder primary).

CONCLUSION

This is the most extensive series examining treatment patterns in patients with U-NENs in the recent era of NEN therapy. The apparent inferior survival for bladder NENs is likely due to the preponderance of PDNECs in this group. As predicted, treatments for U-NENs mirrored that of other more common NENs. In our retrospective cohort, we observed that patients with WD-UNETs treated with peptide receptor radionuclide therapy (PRRT) and everolimus suggested potential activity for disease control in WD-UNETs. Prospective studies are needed to assess the activity of new oncology drugs in UNENs.

Addressing the need for more therapeutic options in neuroendocrine prostate cancer

INTRODUCTION

Neuroendocrine prostate cancer (NEPC) is an aggressive form of prostate cancer frequently seen after prolonged treatment of castration resistant prostate cancer (CRPC). NEPC has become increasingly prevalent over the last 20 years, with a poor prognosis caused by a late diagnosis and limited treatment options. Recent advances in PET/CT imaging and targeted radioimmunotherapy are promising, but more research into additional treatment options is needed.

AREAS COVERED

The aim of this review is to analyze the current imaging and treatment options for NEPC, and to highlight future potential treatment strategies. A Pubmed search for 'Neuroendocrine Prostate Cancer' was performed and relevant articles were reviewed.

EXPERT OPINION

The recent FDA approval and success of 177 PSMA Lutetium in CRPC is promising, as 177 Lutetium could potentially be paired with a NEPC specific biomarker for targeted therapy. Recent laboratory studies pairing DLL3, which is overexpressed in NEPC, with 177 Lutetium and new PET agents have showed good efficacy in identifying and treating NEPC. The success of future development of NEPC therapies may depend on the availability of 177 Lutetium, as current supplies are limited. Further research into additional imaging and treatment options for NEPC is warranted.

Cytomorphology, immunoprofile, and clinicopathologic correlation of metastatic prostatic carcinoma

It may be challenging to diagnose metastatic prostatic carcinoma (PC). This study focused on clinicopathologic correlation, and pitfalls of cytomorphology and immunostains of metastatic PCs. A total of 146 metastatic PCs including 134 (92%) PC without neuroendocrine differentiation-prostatic adenocarcinoma (PAC) and 12 (8%) with neuroendocrine differentiation (PC-NED) were retrieved. Triplicate tissue microarrays (TMA) of 54 surgically excised PCs were constructed for immunostains. Most cases showed Gleason 4 or 5 patterns. Nine percent of cases did not have a prior history of PC and 7% had 2 or more primary malignancies. PAC metastasized more commonly to lymph nodes (49%), and PC-NED metastasized more commonly to liver (58%). Cytologically, metastatic PCs show acini, cribriform, nest, and solid clusters. Most PACs showed conspicuous or prominent nucleoli. PC-NEDs showed typical cytologic features of low-grade or high-grade neuroendocrine neoplasm, or small cell carcinoma features. PACs could be immunoreactive to CDX2 (25%), CK20 (11%), NKX3.1 (99%), PSA (88%), PSAP (78%), and PSMA (92%). PC-NEDs were immunoreactive to neuroendocrine immunomarkers (CD56 [100%], chromogranin [67%], and synaptophysin [100%]) and p63 (25%), and lost expression of prostate-specific markers (NKX3.1, PSA, PSAP, and PSMA). Both PACs and PC-NEDs might be immunoreactive to CK7 (18% versus 33%), GATA3 (4% versus 0%), PAX8 (2% versus 50%, P < .05), and TTF1 (3% versus 57%, P < .05). It is critical to recognize these cytologic features and abbreviation of immunomarkers of metastatic PCs to avoid misinterpretation as metastatic carcinoma from nonprostate organs and inappropriate treatment. In addition, NED may be seen after hormone and chemoradiation treatment.

Molecular mechanisms underlying the development of neuroendocrine prostate cancer

Prostate cancer is the most common non-cutaneous cancer and the second leading cause of cancer-associated deaths among men in the United States. Androgen deprivation therapy (ADT) is the standard of care for advanced prostate cancer. While patients with advanced prostate cancer initially respond to ADT, the disease frequently progresses to a lethal metastatic form, defined as castration-resistant prostate cancer (CRPC). After multiple rounds of anti-androgen therapies, 20-25% of metastatic CRPCs develop a neuroendocrine (NE) phenotype. These tumors are classified as neuroendocrine prostate cancer (NEPC). De novo NEPC is rare and accounts for less than 2% of all prostate cancers at diagnosis. NEPC is commonly characterized by the expression of NE markers and the absence of androgen receptor (AR) expression. NEPC is usually associated with tumor aggressiveness, hormone therapy resistance, and poor clinical outcome. Here, we review the molecular mechanisms underlying the emergence of NEPC and provide insights into the future perspectives on potential therapeutic strategies for NEPC.

Acquired resistance to irradiation or docetaxel is not associated with cross-resistance to cisplatin in prostate cancer cell lines

PURPOSE

Platinum chemotherapy can be considered to treat metastatic castration-resistant prostate cancer (mCRPC) with features of neuroendocrine differentiation. However, platinum compounds are generally only applied after the failure of multiple prior-line treatment options. This study investigated whether acquired resistance against ionizing radiation or docetaxel chemotherapy-two commonly applied treatment modalities in prostate cancer-influences the cisplatin (CDDP) tolerance in mCRPC cell line models.

METHODS

Age-matched parental as well as radio- or docetaxel-resistant DU145 and PC-3 cell lines were treated with CDDP and their sensitivity was assessed by measurements of growth rates, viability, apoptosis, metabolic activity and colony formation ability.

RESULTS

The data suggest that docetaxel resistance does not influence CDDP tolerance in all tested docetaxel-resistant cell lines. Radio-resistance was associated with sensitization to CDDP in PC-3, but not in DU145 cells. In general, DU145 cells tolerated higher CDDP concentrations than PC-3 cells regardless of acquired resistances. Furthermore, non-age-matched treatment-naïve PC-3 cells exhibited significantly different CDDP tolerances.

CONCLUSION

Like patients, different mCRPC cell lines exhibit significant variability regarding CDDP tolerance. The presented in vitro data suggest that previous radiation treatment may be associated with a moderate sensitization to CDDP in an isogenic and age-matched setting. Therefore, previous radiotherapy or docetaxel chemotherapy might be no contraindication against initiation of platinum chemotherapy in selected mCRPC patients.

Anaplastic Features in Advanced Prostate Cancer With and Without DNA Damage Repair Mutations

BACKGROUND

Anaplastic prostate cancer has a poor prognosis with limited treatment options. Seven clinical features of anaplastic prostate cancer have been prospectively identified. In this phase II clinical trial, we identified mutations, including DNA damage repair (DDR) mutations, in patients with metastatic castration-resistant prostate cancer (mCRPC) who were treated with durvalumab and olaparib and determined how many of them can be described as anaplastic, and we examined the overlap between anaplastic features and DDR mutations.

METHODS

Eligible patients with mCRPC received prior enzalutamide, abiraterone, or both. Patients were treated with durvalumab 1500 mg i.v. every 28 days and olaparib 300 mg p.o. every 12 hours until disease progression or unacceptable toxicity. Patients underwent mandatory baseline biopsies of metastatic lesions.

RESULTS

Baseline characteristics were similar between anaplastic and nonanaplastic patients. Eleven patients (20%) displayed clear anaplastic features, and 43 (78.2%) lacked anaplastic features. In the anaplastic group, 2/11 (18.2%) had germline DRR mutations, and 4/11 (36.3%) had somatic DDR mutations. In the nonanaplastic group, 7/43 (16.3%) had germline mutations, and 13/43 (30.2%) had somatic mutations. Median progression-free survival (PFS) times in patients with anaplastic features (6.5 months) and without anaplastic features (5.1 months) were similar (hazard ratio 0.998, P = .996).

CONCLUSIONS

Patients with and without anaplastic features appear to have similar total rates of DDR mutations and also similar rates of somatic and germline DDR mutations. Patients with anaplastic features have a trend toward improved PFS when treated with olaparib and durvalumab compared with nonanaplastic patients.

Involvement of the MEN1 Gene in Hormone-Related Cancers: Clues from Molecular Studies, Mouse Models, and Patient Investigations

MEN1 mutation predisposes patients to multiple endocrine neoplasia type 1 (MEN1), a genetic syndrome associated with the predominant co-occurrence of endocrine tumors. Intriguingly, recent evidence has suggested that MEN1 could also be involved in the development of breast and prostate cancers, two major hormone-related cancers. The first clues as to its possible role arose from the identification of the physical and functional interactions between the menin protein, encoded by MEN1, and estrogen receptor α and androgen receptor. In parallel, our team observed that aged heterozygous Men1 mutant mice developed cancerous lesions in mammary glands of female and in the prostate of male mutant mice at low frequencies, in addition to endocrine tumors. Finally, observations made both in MEN1 patients and in sporadic breast and prostate cancers further confirmed the role played by menin in these two cancers. In this review, we present the currently available data concerning the complex and multifaceted involvement of MEN1 in these two types of hormone-dependent cancers.

Immunotherapy for Metastatic Prostate Cancer: Current and Emerging Treatment Options

The advent of immunotherapy has revolutionized cancer treatment. Prostate cancer has an immunosuppressive microenvironment and a low tumor mutation burden, resulting in low neoantigen expression. The consensus was that immunotherapy would be less effective in prostate cancer. However, recent studies have reported that prostate cancer does have a high number of DNA damage and repair gene defects. Immunotherapies that have been tested in prostate cancer so far have been mainly vaccines and checkpoint inhibitors. A combination of genomically targeted therapies, with approaches to alleviate immune response and thereby make the tumor microenvironment immunologically hot, is promising.

A System Biology-Based Approach for Designing Combination Therapy in Cancer Precision Medicine

In this paper, we have used an agent-based stochastic tumor growth model and presented a mathematical and theoretical perspective to cancer therapy. This perspective can be used to theoretical study of precision medicine and combination therapy in individuals. We have conducted a series of in silico combination therapy experiments. Based on cancer drugs and new findings of cancer biology, we hypothesize relationships between model parameters which in some cases represent individual genome characteristics and cancer drugs, i.e., in our approach, therapy players are delegated by biologically reasonable parameters. In silico experiments showed that combined therapies are more effective when players affect tumor via different mechanisms and have different physical dimensions. This research presents for the first time an algorithm as a theoretical viewpoint for the prediction of effectiveness and classification of therapy sets.

Effective treatment of relapsed prostate small cell carcinoma with amrubicin: report of a case

Standard therapy for metastatic small cell carcinoma of the prostate (SCCP) remains undefined. We have effectively treated relapsed SCCP with amrubicin. A 72-year-old patient, diagnosed with T4N1M0 prostate cancer, started hormonal therapy in May 2012, elsewhere, and his prostate-specific antigen levels remained low. However, pulmonary and hepatic metastases occurred; high neuron-specific enolase levels suggested SCCP, which was confirmed by repeated biopsy at our institution. In October 2016, chemotherapy with irinotecan and cisplatin was initiated for metastases to the lung, liver, and left pelvic lymph nodes, and partial response (PR) was achieved. After six cycles, brain metastases occurred. After ten cycles, his pro-gastrin-releasing peptide levels increased suddenly, and brain and hepatic metastases enlarged. Amrubicin was started in December 2016 and seven cycles were safely completed, with PR and markedly reduced brain metastasis volume, until his pneumonitis-related death in June 2017. Amrubicin may be an effective second-line chemotherapy option for SCCP.

Lineage plasticity-mediated therapy resistance in prostate cancer

Therapy resistance is a significant challenge for prostate cancer treatment in clinic. Although targeted therapies such as androgen deprivation and androgen receptor (AR) inhibition are effective initially, tumor cells eventually evade these strategies through multiple mechanisms. Lineage reprogramming in response to hormone therapy represents a key mechanism that is increasingly observed. The studies in this area have revealed specific combinations of alterations present in adenocarcinomas that provide cells with the ability to transdifferentiate and perpetuate AR-independent tumor growth after androgen-based therapies. Interestingly, several master regulators have been identified that drive plasticity, some of which also play key roles during development and differentiation of the cell lineages in the normal prostate. Thus, further study of each AR-independent tumor type and understanding underlying mechanisms are warranted to develop combinational therapies that combat lineage plasticity in prostate cancer.

A Rich Array of Prostate Cancer Molecular Biomarkers: Opportunities and Challenges

Prostate cancer is the most prevalent non-skin cancer in men and is the leading cause of cancer-related death. Early detection of prostate cancer is largely determined by a widely used prostate specific antigen (PSA) blood test and biopsy is performed for definitive diagnosis. Prostate cancer is asymptomatic in the early stage of the disease, comprises of diverse clinico-pathologic and progression features, and is characterized by a large subset of the indolent cancer type. Therefore, it is critical to develop an individualized approach for early detection, disease stratification (indolent vs. aggressive), and prediction of treatment response for prostate cancer. There has been remarkable progress in prostate cancer biomarker discovery, largely through advancements in genomic technologies. A rich array of prostate cancer diagnostic and prognostic tests has emerged for serum (4K, phi), urine (Progensa, T2-ERG, ExoDx, SelectMDx), and tumor tissue (ConfirmMDx, Prolaris, Oncoytype DX, Decipher). The development of these assays has created new opportunities for improving prostate cancer diagnosis, prognosis, and treatment decisions. While opening exciting opportunities, these developments also pose unique challenges in terms of selecting and incorporating these assays into the continuum of prostate cancer patient care.

Neuroendocrine differentiation in castration resistant prostate cancer. Nuclear medicine radiopharmaceuticals and imaging techniques: A narrative review

BACKGROUND

Androgen Deprivation Therapy (ADT) is the primary treatment for patients suffering from relapsing or advanced prostate cancer (PC). Hormone therapy generally guarantees adequate clinical control of the disease for some years, even in those patients affected by widespread skeletal and soft tissue metastases. Despite ADT, however, most patients treated with hormones eventually progress to castration-resistant prostate cancer (CRPC), for which there are no effective treatments. This clinical reality is an open challenge to the oncologist because of those neoplasms which elaborate neuroendocrine differentiation (NED).

METHODS

An online search of current and past literature on NED in CRPC was performed. Relevant articles dealing with the biological and pathological basis of NED, with nuclear medicine imaging in CRPC and somatostatin treatment in NED were analyzed.

EVIDENCE FROM THE LITERATURE

NED may arise in prostate cancer patients in the late stages of ADT. The onset of NED offers prognostic insight because it reflects a dramatic increase in the aggressive nature of the neoplasm. Several genetic, molecular, cytological and immunohistochemical markers are associated with this transformation. Among these, overexpression of somatostatin receptors, seen through Nuclear Medicine testing, is one of the most studied.

CONCLUSIONS

Preliminary studies show that the overexpression of somatostatin receptors related to NED in CRPC may easily be studied in vivo with PET/CT. This finding offers a potentially useful objective for targeted therapy in CRPC. If the overexpression of SSTRs is shown to afflict a significant segment of patients with CRPC, this will open further study of possible therapeutic options based on this marker.

Function of Tumor Suppressors in Resistance to Antiandrogen Therapy and Luminal Epithelial Plasticity of Aggressive Variant Neuroendocrine Prostate Cancers

Combined loss of tumor suppressors (TSPs), PTEN, TP53, and RB1, is highly associated with small cell carcinoma of prostate phenotype. Recent genomic studies of human tumors as well as analyses in mouse genetic models have revealed a unique role for these TSPs in dictating epithelial lineage plasticity-a phenomenon that plays a critical role in the development of aggressive variant prostate cancer (PCa) and associated androgen therapy resistance. Here, we summarize recently published key observations on this topic and hypothesize a possible mechanism by which concurrent loss of TSPs could potentially regulate the PCa disease phenotype.

[SMALL CELL PROSTATE CANCER PRODUCING SYNDROME OF INAPPROPRIATE SECRETION OF ANTIDIURETIC HORMONE; A CASE REPORT]

A 73-year-old man with progressive prostate cancer visited our hospital after prostate biopsy performed at another hospital. His serum PSA level was 29.02 ng/ml. CT revealed invasion of the bladder, bilateral ureters, and rectum. Otherwise, there was no evidence of metastasis. Pathological findings showed a poorly differentiated adenocarcinoma (Gleason score 4+5) and small cell carcinoma component. Two months after administering combined androgen blockade therapy, he was admitted due to severe hyponatremia caused by the inappropriate secretion of antidiuretic hormone. Furthermore, CT revealed right ureter metastasis, although the PSA levels remained low. Therefore, the patient was put on fluid restriction and sodium administration. After the patient recovered from hyponatremia, chemotherapy, including VP-16 and CDDP, was initiated. However, CT after two chemotherapy cycles revealed disease progression, with multiple bone metastases. Second-line chemotherapy, including CPT-11 and CDDP, was less effective, and the patient died 9 months after the diagnosis.

F-actin reorganization by V-ATPase inhibition in prostate cancer

The vacuolar ATPase (V-ATPase) proton pump sustains cellular pH homeostasis, and its inhibition triggers numerous stress responses. However, the cellular mechanisms involved remain largely elusive in cancer cells. We studied V-ATPase in the prostate cancer (PCa) cell line PC-3, which has characteristics of highly metastatic PCa. V-ATPase inhibitors impaired endo-lysosomal pH, vesicle trafficking, migration, and invasion. V-ATPase accrual in the Golgi and recycling endosomes suggests that traffic of internalized membrane vesicles back to the plasma membrane was particularly impaired. Directed movement provoked co-localization of V-ATPase containing vesicles with F-actin near the leading edge of migrating cells. V-ATPase inhibition prompted prominent F-actin cytoskeleton reorganization. Filopodial projections were reduced, which related to reduced migration velocity. F-actin formed novel cytoplasmic rings. F-actin rings increased with extended exposure to sublethal concentrations of V-ATPase inhibitors, from 24 to 48 h, as the amount of alkalinized endo-lysosomal vesicles increased. Studies with chloroquine indicated that F-actin rings formation was pH-dependent. We hypothesize that these novel F-actin rings assemble to overcome widespread traffic defects caused by V-ATPase inhibition, similar to F-actin rings on the surface of exocytic organelles.

Summary: V-ATPase activates multiple stress responses. In prostate cancer, sub-lethal concentrations of V-ATPase inhibitors trigger widespread traffic defects. F-actin assembles into rings that mimic those seen during regulated exocytosis.

FOXA2 is a sensitive and specific marker for small cell neuroendocrine carcinoma of the prostate

The median survival of patients with small cell neuroendocrine carcinoma is significantly shorter than that of patients with classic acinar-type adenocarcinoma. Small cell neuroendocrine carcinoma is traditionally diagnosed based on histologic features because expression of current immunohistochemical markers is inconsistent. This is a challenging diagnosis even for expert pathologists and particularly so for pathologists who do not specialize in prostate cancer. New biomarkers to aid in the diagnosis of small cell neuroendocrine carcinoma are therefore urgently needed. We discovered that FOXA2, a pioneer transcription factor, is frequently and specifically expressed in small cell neuroendocrine carcinoma compared with prostate adenocarcinoma from published mRNA-sequencing data of a wide range of human prostate cancers. We verified the expression of FOXA2 in human prostate cancer cell lines and xenografts, patient biopsy specimens, tissue microarrays of prostate cancers with lymph node metastasis, primary small cell neuroendocrine carcinoma, and metastatic treatment-related small cell neuroendocrine carcinoma and cases from a rapid autopsy program. FOXA2 expression was present in NCI-H660 and PC3 neuroendocrine cell lines, but not in LNCAP and CWR22 adenocarcinoma cell lines. Of the human prostate cancer specimens, 20 of 235 specimens (8.5%) showed diagnostic histologic features of small cell neuroendocrine carcinoma as judged histologically. Fifteen of 20 small cell neuroendocrine carcinoma tissues (75%) showed strong expression of FOXA2 (staining intensity 2 or 3). FOXA2 expression was also detected in 9 of 215 prostate cancer tissues (4.2%) that were histologically defined as adenocarcinoma. Our findings demonstrate that FOXA2 is a sensitive and specific molecular marker that may be extremely valuable in the pathologic diagnosis of small cell neuroendocrine carcinoma.

[Neuroendocrine prostate cancer: Natural history, molecular features, therapeutic management and future directions]

Neuroendocrine prostate cancer is a rare malignancy with a an adverse prognostic. Histologically, It can be pure (small cells or large cells neuroendocrine carcinoma) or mixed with a adenocarcinoma component. Rarely diagnosed de novo, neuroendocrine prostate cancer is generally associated with advanced stage disease resistant to castration. As such, this histological subtype could represent an aggressive evolution of prostatic adenocarcinoma, through the epithelio-neuroendocrine transdifferentiation mechanism (phenomenon of lineage plasticity). Nonetheless, neuroendocrine prostate cancer is a heterogeneous malignancy with multiple histopathological variants showing distinct clinical features. The broad variety of molecular analyses could help to understand the ontogeny of this histological subtype and its signaling pathways. This may also allow identifying diagnostic and prognostic biomarkers as well as potential molecular targets. However, treatment options are currently limited and consist only in platinium-based chemotherapy for advanced stage disease.

Role of tumor microenvironment in tumorigenesis

Tumorigenesis is a complex and dynamic process, consisting of three stages: initiation, progression, and metastasis. Tumors are encircled by extracellular matrix (ECM) and stromal cells, and the physiological state of the tumor microenvironment (TME) is closely connected to every step of tumorigenesis. Evidence suggests that the vital components of the TME are fibroblasts and myofibroblasts, neuroendocrine cells, adipose cells, immune and inflammatory cells, the blood and lymphatic vascular networks, and ECM. This manuscript, based on the current studies of the TME, offers a more comprehensive overview of the primary functions of each component of the TME in cancer initiation, progression, and invasion. The manuscript also includes primary therapeutic targeting markers for each player, which may be helpful in treating tumors.

Rapid progression of mixed neuroendocrine carcinoma-acinar adenocarcinoma of the prostate: A case report

The current study presents the case of a 78-year-old male with mixed neuroendocrine (NE) carcinoma-acinar adenocarcinoma of the prostate. The patient received endocrine therapy (maximal androgen blockade) after the initial diagnosis resulting in a significant decrease in serum prostate-specific antigen (PSA) level. The patient underwent transurethral resection of the prostate after 6 months of androgen-deprivation therapy for extraordinarily salient difficulty in urination, and histopathology demonstrated mixed NE carcinoma-acinar adenocarcinoma once again. The NE prostate cancer progressed rapidly even though the serum PSA was controlled at a low level on account of the endocrine therapy. Previous treatment protocols were replaced by combined chemotherapy and endocrine therapy, and the patient responded well. The patient's serum PSA remained at a low level, however, urethral dilatation for acute urinary retention was required again 5 months later and the lower urinary tract symptoms became increasingly evident. The patient eventually died of cachexia.. These findings indicate that mixed NE carcinoma-acinar adenocarcinoma has a higher degree of malignancy and that endocrine therapy for prostate cancer has a propensity to facilitate progression of this tumor.

[SMALL CELL CARCINOMA OF THE PROSTATE: A CASE REPORT OF RELATIVE LONG-TERM SURVIVAL]

Small cell carcinoma of the prostate (SCCP) is rare, and no standard treatment regimen has yet been established. The overall prognosis remains poor. We experienced a case who obtained relative long-term survival with two types of chemotherapy treatments. A 69-year-old man underwent combined androgen blockade (CAB) with a diagnosis of prostate adenocarcinoma (Gleason score = 5 + 3) that was staged T3bN1M1b (initial PSA = 352 ng/ml). Twenty-five months after hormonal therapy, the level of serum PSA had elapsed remain low, however, FDG-PET/CT revealed high value at the lymph node of para-aortic and pelvic lesion. The levels of serum NSE and Pro-GRP elevated, and a prostate re-biopsy revealed a small cell carcinoma. Therefore, he was treated with 12-cycles of combination chemotherapy consisting of etoposide and carboplatin. Then, disease has progressed, so he was changed to second line chemotherapy with amrubicin. He underwent 12-cycles chemotherapy with amrubicin, but he died of cancer 39 months after the initial treatment of SCCP.

Neuroendocrine tumours in rare sites: differences in nomenclature and diagnostics-a rare and ubiquitous histotype

The diagnosis of neuroendocrine tumours in typical sites, as gastrointestinal tract and lung, is based upon well-coded criteria that have become familiar to most of the pathologists. Much more difficult is the recognition and allocation of proper nomenclature to be referred to the same histotype in locations where these tumours have a lower incidence. The aim of our review was to provide a quick handbook of the main diagnostic pitfalls known in literature that can interpose in the histopathological examination of neuroendocrine tumours in rare sites (urinary system and male genital organs, female genital organs, head and neck and breast).

Differentially methylated genes and androgen receptor re-expression in small cell prostate carcinomas

Small cell prostate carcinoma (SCPC) morphology is rare at initial diagnosis but often emerges during prostate cancer progression and portends a dismal prognosis. It does not express androgen receptor (AR) or respond to hormonal therapies. Clinically applicable markers for its early detection and treatment with effective chemotherapy are needed. Our studies in patient tumor-derived xenografts (PDX) revealed that AR-negative SCPC (AR(-)SCPC) expresses neural development genes instead of the prostate luminal epithelial genes characteristic of AR-positive castration-resistant adenocarcinomas (AR(+)ADENO). We hypothesized that the differences in cellular lineage programs are reflected in distinct epigenetic profiles. To address this hypothesis, we compared the DNA methylation profiles of AR(-) and AR(+) PDX using methylated CpG island amplification and microarray (MCAM) analysis and identified a set of differentially methylated promoters, validated in PDX and corresponding donor patient samples. We used the Illumina 450K platform to examine additional regions of the genome and the correlation between the DNA methylation profiles of the PDX and their corresponding patient tumors. Struck by the low frequency of AR promoter methylation in the AR(-)SCPC, we investigated this region's specific histone modification patterns by chromatin immunoprecipitation. We found that the AR promoter was enriched in silencing histone modifications (H3K27me3 and H3K9me2) and that EZH2 inhibition with 3-deazaneplanocin A (DZNep) resulted in AR expression and growth inhibition in AR(-)SCPC cell lines. We conclude that the epigenome of AR(-) is distinct from that of AR(+) castration-resistant prostate carcinomas, and that the AR(-) phenotype can be reversed with epigenetic drugs.

A biomimetic approach to hormone resistant prostate cancer cell isolation using inactivated Sendai virus (HVJ-E)

A versatile immobilization method of inactivated Sendai virus (HVJ-E) for metastatic prostate cancer cell isolation.

Comprehensive serial molecular profiling of an "N of 1" exceptional non-responder with metastatic prostate cancer progressing to small cell carcinoma on treatment

Importance

Small cell carcinoma/neuroendocrine prostate cancer (NePC) is a lethal, poorly understood prostate cancer (PCa) subtype. Controversy exists about the origin of NePC in this setting.

Objective

To molecularly profile archived biopsy specimens from a case of early-onset PCa that rapidly progressed to NePC to identify drivers of the aggressive course and mechanisms of NePC origin and progression.

Design, setting, and participants

A 47-year-old patient presented with metastatic prostatic adenocarcinoma (Gleason score 9). After a 6-month response to androgen deprivation therapy, the patient developed jaundice and liver biopsy revealed exclusively NePC. Targeted next generation sequencing (NGS) from formalin-fixed paraffin-embedded (FFPE)-isolated DNA was performed from the diagnostic prostate biopsy and the liver biopsy at progression.

Intervention

Androgen deprivation therapy for adenocarcinoma followed by multiagent chemotherapy for NePC.

Main outcomes and measures

Identification of the mutational landscape in primary adenocarcinoma and NePC liver metastasis. Whether the NePC arose independently or was derived from the primary adenocarcinoma was considered based on mutational profiles.

Results

A deleterious somatic SMAD4 L535fs variant was present in both prostate and liver specimens; however, a TP53 R282W mutation was exclusively enriched in the liver specimen. Copy number analysis identified concordant, low-level alterations in both specimens, with focal MYCL amplification and homozygous PTEN, RB1, and MAP2K4 losses identified exclusively in the NePC specimen. Integration with published genomic profiles identified MYCL as a recurrently amplified in NePC.

Conclusions and relevance

NGS of routine biopsy samples from an exceptional non-responder identified SMAD4 as a driver of the aggressive course and supports derivation of NePC from primary adenocarcinoma (transdifferentiation).

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-015-0204-7) contains supplementary material, which is available to authorized users.

[A CASE OF PROSTATE CANCER WITH UNUSUAL PATTERN OF RECURRENCE AFTER RADIOTHERAPY]

An 82-year-old man underwent radiotherapy (brachytherapy, external beam radiotherapy) for prostate cancer, followed approximately five years later by endocrine therapy for biochemical recurrence, which controlled the prostate-specific antigen (PSA) level. His later admission due to severe gross hematuria and dysuria is described. Computed tomography and magnetic resonance imaging findings revealed a cystic tumor continuous with the prostate between the prostate and rectum, and this tumor was thought to be the cause of the hematuria and dysuria. Transrectal biopsy and transurethral resection of the prostate were performed for pathological diagnosis and improvement of dysuria. The pathological diagnosis was remnant prostate cancer, and the cystic tumor was thought to have developed as a result of prostate cancer recurrence. Although chemotherapy using docetaxel was considered postoperatively, the patient refused this treatment. Even though the PSA level was under control, the patient's condition progressed rapidly, with onset of pulmonary and cervical lymph node metastases within a short period of time, and the patient subsequently died.

Prostate cancer and neuroendocrine differentiation: more neuronal, less endocrine?

Neuroendocrine differentiation (NED) marks a structural and functional feature of certain cancers, including prostate cancer (PCa), whereby the malignant tissue contains a significant proportion of cells displaying neuronal, endocrine, or mixed features. NED cells produce, and can secrete, a cocktail of mediators commonly encountered in the nervous system, which may stimulate and coordinate cancer growth. In PCa, NED appears during advanced stages, subsequent to treatment, and accompanies treatment resistance and poor prognosis. However, the term “neuroendocrine” in this context is intrinsically vague. This article seeks to provide a framework on which a unified view of NED might emerge. First, we review the mutually beneficial interplay between PCa and neural structures, mainly supported by cell biology experiments and neurological conditions. Next, we address the correlations between PCa and neural functions, as described in the literature. Based upon the integration of clinical and basic observations, we suggest that it is legitimate to seek for true neural differentiation, or neuromimicry, in cancer progression, most notably in PCa cells exhibiting what is commonly described as NED.

β-Adrenergic Receptor Signaling in Prostate Cancer

Enhanced sympathetic signaling, often associated with obesity and chronic stress, is increasingly acknowledged as a contributor to cancer aggressiveness. In prostate cancer, intact sympathetic nerves are critical for tumor formation, and sympathectomy induces apoptosis and blocks tumor growth. Perineural invasion, involving enrichment of intra-prostatic nerves, is frequently observed in prostate cancer and is associated with poor prognosis. β₂-adrenergic receptor (ADRB2), the most abundant receptor for sympathetic signals in prostate luminal cells, has been shown to regulate trans-differentiation of cancer cells to neuroendocrine-like cells and to affect apoptosis, angiogenesis, epithelial–mesenchymal transition, migration, and metastasis. Epidemiologic studies have shown that use of β-blockers, inhibiting β-adrenergic receptor activity, is associated with reduced prostate cancer-specific mortality. In this review, we aim to present an overview on how β-adrenergic receptor and its downstream signaling cascade influence the development of aggressive prostate cancer, primarily through regulating neuroendocrine differentiation.

Neuroendocrine Prostate Cancer (NEPC) progressing from conventional prostatic adenocarcinoma: factors associated with time to development of NEPC and survival from NEPC diagnosis-a systematic review and pooled analysis

PURPOSE

An often under-recognized late manifestation of prostate adenocarcinoma (PCa) is the development of treatment-related neuroendocrine prostate cancer (NEPC). The aim of this study is to identify the risk factors related to survival after NEPC diagnosis (NEPCS) and time from initial diagnosis of PCa to development of NEPC (TTNEPC).

PATIENTS AND METHODS

A literature search on NEPC was performed using databases such as MEDLINE and EMBASE. Studies were eligible if outcomes data (NEPCS and/or TTNEPC) were reported in patients with a prior history of PCa and histopathologically confirmed NEPC. NEPCS and TTNEPC were evaluated using the Cox regression model with the robust sandwich estimates of the covariance matrix.

RESULTS

There were 54 eligible publications, contributing 123 patients. The median TTNEPC was 20 months. In multivariable analyses, the Gleason score was significantly associated with shorter TTNEPC (hazard ratio [HR], 1.66; P = .032). The median NEPCS was 7 months. In multivariable analyses, the number of organs with metastatic disease at NEPC was significantly associated with shorter NEPCS (HR, 3.31; P = .001). Type of treatment after NEPC was significantly associated with longer NEPCS, with HRs of 0.66 (radiotherapy v palliative therapy; P = .034), 0.38 (chemotherapy v palliative therapy; P = .018), and 0.29 (chemoradiotherapy v palliative therapy; P = .012), respectively.

CONCLUSION

Treatment-related NEPC is an often under-recognized late manifestation of PCa with poor prognosis. Our study found that Gleason score was the only independent factor contributing to TTNEPC. Once NEPC is diagnosed, type of treatment and the number of organs with metastatic disease were the most important factors related to survival.

Small cell carcinoma of the prostate

Pure small-cell carcinoma (SCC) of the prostate is a rare entity and one of the most aggressive malignancies of the prostate. Histologically, prostatic SCCs of the prostate are part of a spectrum of anaplastic tumours of the prostate and are similar to SCCs of the lungs. In most cases, SCC of the prostate is associated with conventional prostatic adenocarcinoma. Both components of these mixed tumours frequently share molecular alterations such as ERG gene rearrangements or AURKA and MYCN amplifications, suggesting a common clonal origin. The clinical behaviour of small-cell prostate carcinomas is characterized by extensive local disease, visceral disease, and low PSA levels despite large metastatic burden. Commonly, the emergence of the SCC occurs in patients with high-grade adenocarcinoma who are often treated with androgen deprivation treatment (ADT). However, SCCs do not usually benefit from ADT. A biopsy of accessible lesions is strongly recommended to identify those with SCC pathological features, as management is undoubtedly affected by this finding. Chemotherapy is the standard approach for treating patients with either localized or advanced prostatic SCC. Despite the emergence of more-aggressive treatment modalities, the prognosis of men with prostatic SCC remains dismal.

Genitourinary small-cell carcinoma: a single-institution experience

BACKGROUND

Small-cell carcinomas (sccs) of the genitourinary (gu) tract are rare systemic diseases, and there is no standard treatment strategy for patients with this malignancy. The objectives of the present study were to report the management and outcome of patients with scc of the gu tract treated at a tertiary-care institution from 1982 to 2009.

METHODS

In a chart review of all patients diagnosed with scc of the gu tract between 1982 and 2009, data on demographics, clinical and pathologic characteristics, treatment, and patient outcomes were collected.

RESULTS

The 58 patients identified had scc in the following primary sites: urinary bladder (n = 35), prostate (n = 17), and upper urinary tract (n = 6). In 38 patients (66%), the scc was of pure histology; in the remainder, histology was mixed. Overall, 28 patients had limited-stage disease; 24 had extensive-stage disease; and staging was unknown in 6 patients. Median survival for the entire cohort was 7.5 months, with extensive-stage disease being identified as a poor prognostic factor (survival was 22.0 months for limited-stage patients and 4.1 months for extensive-stage patients, p < 0.001). Based on site, prostate patients fared worst, with a median survival of only 5.1 months. Compared with best supportive care, treatment was associated with better outcomes (median survival: 12.3 months vs. 2.3 months, p < 0.0001).

CONCLUSIONS

Small-cell cancer of the gu tract is an aggressive cancer, with a poor prognosis overall. Although there is no standard of care, patients should be treated using a multimodality approach analogous to that used in the treatment of small-cell lung cancer.

Platinum-based chemotherapy for variant castrate-resistant prostate cancer

PURPOSE

Clinical features characteristic of small-cell prostate carcinoma (SCPC), "anaplastic," often emerge during the progression of prostate cancer. We sought to determine the efficacy of platinum-based chemotherapy in patients meeting at least one of seven prospectively defined "anaplastic" clinical criteria, including exclusive visceral or predominantly lytic bone metastases, bulky tumor masses, low prostate-specific antigen levels relative to tumor burden, or short response to androgen deprivation therapy.

EXPERIMENTAL DESIGN

A 120-patient phase II trial of first-line carboplatin and docetaxel (CD) and second-line etoposide and cisplatin (EP) was designed to provide reliable clinical response estimates under a Bayesian probability model with early stopping rules in place for futility and toxicity.

RESULTS

Seventy-four of 113 (65.4%) and 24 of 71 (33.8%) were progression free after four cycles of CD and EP, respectively. Median overall survival (OS) was 16 months [95% confidence interval (CI), 13.6-19.0 months]. Of the seven "anaplastic" criteria, bulky tumor mass was significantly associated with poor outcome. Lactic acid dehydrogenase strongly predicted for OS and rapid progression. Serum carcinoembryonic antigen (CEA) concentration strongly predicted OS but not rapid progression. Neuroendocrine markers did not predict outcome or response to therapy.

CONCLUSION

Our findings support the hypothesis that patients with "anaplastic" prostate cancer are a recognizable subset characterized by a high response rate of short duration to platinum-containing chemotherapies, similar to SCPC. Our results suggest that CEA is useful for selecting therapy in men with castration-resistant prostate cancer and consolidative therapies to bulky high-grade tumor masses should be considered in this patient population.

A useful treatment for patients with advanced mixed-type small cell neuroendocrine carcinoma of the prostate: A case report

Treating extended prostatic small cell neuroendocrine carcinoma (PSCNC) is extremely difficult and no standard treatment has yet been established. We experienced a case of advanced mixed-type PSCNC in which the patient achieved long-term survival and local control following combined therapy. Locally advanced PSCNC causing lower urinary obstruction was detected during androgen-ablation therapy for stage D2 mixed adenocarcinoma PSCNC. The patient was treated with intra-arterial infusion chemotherapy using a reservoir system and external-beam radiotherapy (EBRT) to the whole pelvis and local tumor. After chemoradiotherapy, the patient’s lower urinary obstruction was reduced and did not return during the remaining 40 months of the patient’s life. The patient survived for 70 months following the start of the androgen-ablation therapy. The present study reports a useful treatment for advanced mixed-type PSCNC, androgen-ablation therapy and chemoradiotherapy. The present results also suggest that the prognostic factors for advanced mixed-type PSCNC are the sensitivity of the conventional adenocarcinoma to androgen-ablation therapy, degree of metastasis and extent of the small cell neuroendocrine carcinoma component.

The prognostic significance of loss of the androgen receptor and neuroendocrine differentiation in prostate biopsy specimens among castration-resistant prostate cancer patients

Prostate cancer (PCa) is a leading cause of mortality, and despite good response to androgen ablation this response is eventually lost. In the present study, androgen receptor (AR) expression and neuroendocrine differentiation (NED) were evaluated in hormone-sensitive (HSPC) and castration-resistant prostate cancers (CRPC). Prostate tissues were obtained from 20 HSPC patients at diagnosis and 28 CRPC patients at castration-resistant progression. AR, chromogranin A (CGA) and neuron-specific enolase (NSE) were evaluated by immunohistochemical staining (IHS) in representative positive cores for PCa. IHS intensity was graded as negative, 0; positive, 1+ and strongly positive, 2+. The proportion of the 1+ and 2+ areas in PCa cells was determined. PCa was considered to be in NED if ≥50% of the tumor cells were 1+ or 2+ for CGA or NSE. The observed IHS intensity (0/1+/2+) for AR, CGA and NSE was 0/4/16, 5/11/4 and 11/4/5 in HSPC patients and 9/3/16, 5/8/15 and 8/4/16 in CRPC patients, respectively. AR expression was positive in all the HSPC and 19/28 CRPC patients (P=0.0049). NED was observed in 9/20 HSPC and 20/28 CRPC patients (P=0.0649). NED was significantly associated with a negative AR expression in CRPC patients (P=0.0292). Multivariate analysis revealed that age, AR expression and strong NED were independent parameters for prognosis following castration-resistant progression. In conclusion, prostate biopsy following castration-resistant progression was necessary. AR was lost in a subset of CRPC. NED was observed more frequently in CRPC vs. HSPC and was associated with a worse prognosis.

Small cell carcinoma of the prostate after high-dose-rate brachytherapy for low-risk prostatic adenocarcinoma

In the present study, we describe an 80-year-old patient who developed prostatic small cell carcinoma (SCC) following high-dose-rate brachytherapy (HDR-BT) for low-risk prostatic adenocarcinoma. The patient received one implant of Ir-192 and 7 fractions of 6.5 Gy within 3.5 days, for a total prescribed dose of 45.5 Gy. A total of 27 months after HDR-BT, the patient complained of difficulty in urinating. His serum prostate-specific antigen (PSA) levels were 3.2 ng/ml. Systemic examination revealed an enlargement of the prostate, urethral stenosis, pelvic lymph node swelling and multiple lung and bone lesions. His serum neuron-specific enolase (NSE) levels were elevated to 120 ng/ml. A prostate needle biopsy was performed for pathological examination. Histologically, there were tumor cells with hyperchromatic nuclei and scant cytoplasm showing a solid or trabecular growth pattern. Immunohistochemically, they were positive for AE1/AE3, CD56 and synaptophysin, and negative for PSA, PAP and CD57. These findings are consistent with SCC of the prostate. A review of the prostate needle biopsy specimen prior to HDR-BT did not reveal any tumor cells positive for chromogranin A, nor synaptophysin. The final diagnosis was SCC of the prostate with local progression, with lung, lymph node and bone metastases. Three cycles of etoposide/cisplatin (EP) were administered. A greater than 50% decrease in the serum NSE levels was observed. However, there was no objective response. Due to the deterioration of the patient's general condition, EP was discontinued. One month later, his serum NSE showed a rapid increase to 210 ng/ml with aggressive local progression and the patient succumbed to the disease 5.5 months after the start of EP therapy.

Pathogenesis of prostatic small cell carcinoma involves the inactivation of the P53 pathway

Small cell neuroendocrine carcinoma (SCNC) of the prostate is a variant form of prostate cancer that occurs de novo or as a recurrent tumor in patients who received hormonal therapy for prostatic adenocarcinoma. It is composed of pure neuroendocrine (NE) tumor cells, but unlike the scattered NE cells in benign prostate and adenocarcinoma that are quiescent, the NE cells in SCNC are highly proliferative and aggressive, causing death in months. In this study, we provide evidence that interleukin 8 (IL8)-CXCR2-P53 (TP53) signaling pathway keeps the NE cells of benign prostate and adenocarcinoma in a quiescent state normally. While P53 appears to be wild-type in the NE cells of benign prostate and adenocarcinoma, immunohistochemical studies show that the majority of the NE tumor cells in SCNC are positive for nuclear p53, suggesting that the p53 is mutated. This observation is confirmed by sequencing of genomic DNA showing p53 mutation in five of seven cases of SCNC. Our results support the hypothesis that p53 mutation leads to inactivation of the IL8-CXCR2-p53 signaling pathway, resulting in the loss of an important growth inhibitory mechanism and the hyper-proliferation of NE cells in SCNC. Therefore, we have identified potential cells of origin and a molecular target for prostatic SCNC that are very different from those of conventional adenocarcinoma, which explains SCNC's distinct biology and the clinical observation that it does not respond to hormonal therapy targeting androgen receptor signaling, which produces short-term therapeutic effects in nearly all patients with prostatic adenocarcinoma.

Next generation sequencing of prostate cancer from a patient identifies a deficiency of methylthioadenosine phosphorylase, an exploitable tumor target

Castrate-resistant prostate cancer (CRPC) and neuroendocrine carcinoma of the prostate are invariably fatal diseases for which only palliative therapies exist. As part of a prostate tumor sequencing program, a patient tumor was analyzed using Illumina genome sequencing and a matched renal capsule tumor xenograft was generated. Both tumor and xenograft had a homozygous 9p21 deletion spanning the MTAP, CDKN2, and ARF genes. It is rare for this deletion to occur in primary prostate tumors, yet approximately 10% express decreased levels of methylthioadenosine phosphorylase (MTAP) mRNA. Decreased MTAP expression is a prognosticator for poor outcome. Moreover, it seems that this deletion is more common in CRPC than in primary prostate cancer. We show for the first time that treatment with methylthioadenosine and high dose 6-thioguanine causes marked inhibition of a patient-derived neuroendocrine xenograft growth while protecting the host from 6-thioguanine toxicity. This therapeutic approach can be applied to other MTAP-deficient human cancers as deletion or hypermethylation of the MTAP gene occurs in a broad spectrum of tumors at high frequency. The combination of genome sequencing and patient-derived xenografts can identify candidate therapeutic agents and evaluate them for personalized oncology.

Prostatic carcinomas with neuroendocrine differentiation diagnosed in needle biopsies, a morphologic study of 7 cases among 465 sequential biopsies in a tertiary cancer center

PURPOSE

Neuroendocrine carcinomas (NEC) of the prostate are rare, with only a few series hitherto reported. The objective of this study was to assess in a single institution the clinical and morphologic characteristics of neuroendocrine carcinomas diagnosed in needle core biopsies.

MATERIALS AND METHODS

The current study analyses seven cases diagnosed in needle biopsies at a large tertiary regional cancer center from Northeastern Brazil. Two pathologists reviewed specimens retrospectively, and demographic and morphologic characteristics were compared to 458 acinar tumors diagnosed in the same period.

RESULTS

There were five small cell carcinomas and two low-grade neuroendocrine carcinomas (carcinoid). NEC were associated with an acinar component in 5/7 cases and the Gleason score of the acinar component was always > 6. The number of cores involved in prostates with NEC was greater (65% compared to 24% of acinar tumors, p < 0.05). The mean PSA at diagnosis was 417.7 (range 5.7-1593, SD 218.3), compared to 100.5 (p = 0.1) of acinar tumors (range 0.3-8545, SD 22.7). Prostates harboring NEC were bigger (p < 0.001, mean volume 240 mL vs. 53 mL of acinar tumors). Treatment of NEC included palliative surgery, chemotherapy, and hormonal therapy.

CONCLUSIONS

NEC of the prostate is rare and often associated with a high-grade acinar component. Prostates with NEC tend to be larger and involve a greater number of cores than acinar tumors. PSA at diagnosis does not seem to predict the presence of NE tumors in needle biopsy.

PC3 is a cell line characteristic of prostatic small cell carcinoma

BACKGROUND

The majority of the prostatic cancers are adenocarcinomas characterized by glandular formation and the expression of luminal differentiation markers androgen receptor (AR) and prostate-specific antigen (PSA). Most adenocarcinomas are indolent and androgen-dependent. Hormonal therapy that inhibits AR signaling produces symptomatic relief in patients with advanced and metastatic adenocarcinomas. Prostatic small cell neuroendocrine carcinoma (SCNC) is a variant form of prostate cancer (PC). In contrast to adenocarcinoma, the tumor cells of SCNC do not form glands and are negative for AR and PSA. SCNC is extremely aggressive and does not respond to hormonal therapy. The purpose of this study was to compare the important and relevant features of two most commonly used PC cell lines, LNCaP and PC3, with prostatic adenocarcinoma and SCNC.

METHODS

Xenograft tumors of LNCaP and PC3 were prepared and compared with human prostatic adenocarcinoma and SCNC for the expression of key signaling molecules by immunohistochemistry and Western blot analysis.

RESULTS

LNCaP cells express AR and PSA and their growth is inhibited by androgen withdrawal, similar to human prostatic adenocarcinoma. PC3 cells do not express AR and PSA and their proliferation is independent of androgen, similar to SCNC. Adenocarcinoma cells and LNCaP cells are negative for neuroendocrine markers and stem cell-associated marker CD44 while SCNC and PC3 cells are positive. LNCaP cells have identical cytokeratin profiles to adenocarcinoma while PC3 cells have cytokeratin profiles similar to SCNC.

CONCLUSION

LNCaP cells share common features with adenocarcinoma while PC3 cells are characteristic of SCNC.

Review of small cell carcinomas of the prostate

Small cell carcinoma of the prostate is a rare neoplasm, with only a few series hitherto reported. A little less than half of the cases are associated with conventional acinar adenocarcinoma, which are usually high grade. Although consensus has not been reached, the majority of patients with small cell neuroendocrine carcinoma of the prostate have advanced disease at diagnosis and disproportionally low PSA levels compared to patients with conventional acinar adenocarcinoma. Treatment consists mainly of chemotherapy associated with surgery. Radiation therapy is reserved for selected cases. This study reviews the most up-to-date information on small cell carcinomas of the prostate.

Small-cell prostate carcinoma: A retrospective analysis of five newly reported cases

Five cases of small-cell carcinoma (SCC) of prostate were identified, at the Rhode Island Hospital and the Miriam Hospital from 1984 to 2006, with an average age of 71 years at the time of diagnosis. Three of these patients had a prior diagnosis of prostatic adenocarcinoma, with all of the five patients receiving anti-androgen treatment. The average time between the diagnosis of adenocarcinoma and of SCC in these patients was 6.7 years. The PSA levels varied greatly, with two patients possessing markedly elevated levels and the remaining patients with normal levels. Approximately 3/5 patients developed liver metastases, 2/5 patients had bone metastases, and 1/5 patients developed carcinomatous meningitis. Of the four patients who expired, the median survival time after diagnosis of SCC was 3.6 months (0.5–12 months).

Neuroendocrine prostate cancer xenografts with large-cell and small-cell features derived from a single patient's tumor: morphological, immunohistochemical, and gene expression profiles

BACKGROUND

Small-cell carcinoma (SCC) of the prostate is an AR-negative variant of prostate cancer found at progression in 10-20% of castrate-resistant disease. Its finding predicts a distinct clinical course and a poor prognosis. Large-cell neuroendocrine carcinoma (LCNEC) is a much rarer variant that behaves similarly to SCC. The biological mechanisms that drive these disease variants are poorly understood.

METHODS

Eight tumor fragments from the salvage pelvic exenteration specimen of a patient with castrate-resistant prostate carcinoma were subcutaneously implanted into 6- to 8-week-old male CB17 SCID mice. Serial tissue sections and tissue microarrays of the resulting MDA PCa 144 xenograft lines were used for histopathologic and immunohistochemical characterization of the xenografts and their tissue of origin. RNA from two representative xenograft sublines was used for gene-expression profiling.

RESULTS

All eight fragments formed tumors: four of the MDA PCa 144 xenograft sublines had morphologic characteristics of SCC and four, of LCNEC. All retained high fidelity to their parent tumor tissue, which remained stable through serial passages. Morphological transitions in the specimen of origin suggested LCNEC represents an intermediate step between adenocarcinoma and SCC. Over 2,500 genes were differentially expressed between the SCC (MDA PCa 144-13) and the LCNEC (MDA PCa 144-4) sublines and enriched in "Nervous System Development" Gene Ontology subtree.

CONCLUSION

The eight xenograft models described represent the spectrum of neuroendocrine carcinomas in prostate cancer and will be valuable preclinical tools to study the pathogenesis of and therapy targets for this increasingly recognized subset of lethal prostate cancer.

The relationship of neuroendocrine carcinomas to anti-tumor therapies in TRAMP mice

BACKGROUND

Neuroendocrine differentiation and neuroendocrine carcinoma (NEC) have been linked to androgen deprivation in prostate cancers. No previous study has directly connected neuroendocrine phenotypes to chemotherapy. The pathogenesis of prostatic NEC has not yet been determined.

METHODS

Using the transgenic adenocarcinoma of mouse prostate (TRAMP) model, we studied tumor progression after hormone ablation (castration) and/or chemotherapy (docetaxel), and analyzed the incidence of NEC as a function of the anti-tumor therapies. Non-treated mice were used as controls. Protein expressions in tumor tissues were analyzed by Western blots and immunohistochemistry.

RESULTS

Although all animals developed prostate cancer, no NEC was found in control mice. However, over 30% of the mice that received an anti-tumor therapy developed NEC. A similar incidence of NEC was found in the castration-only and docetaxel-only treatment groups, while a higher incidence was observed in the combined treatment (castration and docetaxel) group. The NEC-bearing mice had smaller tumors in their prostates and lived longer than mice with adenocarcinoma (ADC-only). However, NEC tumors had a higher proliferative index and greater potential for metastasis and drug-resistance, as evidenced by significantly higher expression levels of PCNA, S100A4, and Pgp, but lower levels of E-cadherin. SV40 T-antigen was highly expressed in both NEC and ADC tumors.

CONCLUSIONS

Stress induced by anti-cancer treatments may play a role in NEC development. Although NEC and ADC differ in their expressions of many proteins, a high level of SV40 T-antigen in both tumor types suggest a common progenitor..

Neuroendocrine differentiation of localized prostate cancer during endocrine therapy

A 74-year-old male was treated with endocrine therapy for localized prostate cancer. After 25 months he complained of a swollen neck, and was diagnosed with prostate cancer with lymph node metastasis of neuroendocrine differentiation. Neuroendocrine differentiation without elevation of conventional tumor markers is rare during the initial recurrent course of localized prostate cancer.

Extrapulmonary small cell carcinoma localized in lymph nodes: is it a different clinical entity?

BACKGROUND

Extrapulmonary small cell carcinomas (EPSCC) can clinically progress differently depending on the primary site of disease involvement. This review is focused on patients with small cell carcinoma (SmCC) exclusively localized in a lymph node or in multiple lymph nodes without any evidence of a primary tumor in any other organ.

METHODS

We searched the period 1980 to 2007 in the PubMed database and identified 11 publications in the English language presenting at least one case of SmCC. In total 28 individual patients were included in the present study. They were scrutinized in terms of epidemiology, clinical presentation, staging, pathology, etiology, treatment and prognosis.

RESULTS

Characteristics such as age, gender and smoking were similar to those seen in other EPSCCs. Median survival was not reached (42+, range, 9.1 to 100 months). The survival rate was found to be 79% at 3 years. Seventy-seven percent of the patients had limited stage disease. These patients completely responded to surgical therapy, chemotherapy, radiotherapy or to a combination of these treatments. Seventy-one percent of the patients with limited stage SmCC localized in lymph nodes were recurrence-free during the study periods.

DISCUSSION

Our review patient group with SmCC localized in lymph nodes exhibited an excellent clinical behavior and survival results when compared to other patients with pulmonary and non-pulmonary SmCCs. SmCCs localized in lymph nodes may be a separate clinical entity.