Small cell carcinoma of the prostate. A morphologic and immunohistochemical study of 95 cases. Am J Surg Pathol. 2008;32:65-71. [PMID: 18162772 DOI: 10.1097/PAS.0b013e318058a96b]

Small-Cell Carcinoma of the Prostate: Report of Outcomes of Localized Disease Using the National Cancer Database

BACKGROUND

Small-cell carcinoma of the prostate (SCCP) is a rare but aggressive prostate cancer histology. We studied the reported comparative outcomes of the efficacy of radiotherapy (RT) versus surgery for nonmetastatic SCCP.

METHODS

The National Cancer Database (NCDB) was queried for nonmetastatic disease diagnosed from 2004 to 2015 as SCCP (defined as having a component of SCCP) receiving a single definitive local control modality (RT or surgery).

RESULTS

A total of 243 patients were included (177 RT and 66 surgery). A total of 142 patients received chemotherapy (CHT). Mean age was 68 years. One hundred forty patients had adenocarcinoma concurrently with the SCCP while 103 patients had pure histology. For pure histology, multivariable analysis (MVA) showed nonacademic facility, stage 4 disease, and poorly differentiated grade were associated with worse survival. On MVA, receipt of CHT (hazard ratio [HR] = 0.84, P = .644) or receipt of androgen deprivation therapy (HR = 0.88, P = .715) did not affect overall survival. Receipt of RT was nonsignificant compared to surgery (HR = 0.75, P = .475). For mixed histology, MVA showed receipt of CHT and prostate-specific antigen > 20 ng/mL were associated with worse survival. Receipt of androgen deprivation therapy (HR = 1.35, P = .414) did not affect overall survival. Receipt of RT was also nonsignificant compared to surgery (HR = 1.42, P = .344).

CONCLUSION

RT and surgery for nonmetastatic SCCP yield comparable options as local therapies.

Histone demethylase PHF8 drives neuroendocrine prostate cancer progression by epigenetically upregulating FOXA2

Neuroendocrine prostate cancer (NEPC) is a more aggressive subtype of castration-resistant prostate cancer (CRPC). Although it is well established that PHF8 can enhance prostate cancer cell proliferation, whether PHF8 is involved in prostate cancer initiation and progression is relatively unclear. By comparing the transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with or without Phf8 knockout, we systemically examined the role of PHF8 in prostate cancer development. We found that PHF8 plays a minimum role in initiation and progression of adenocarcinoma. However, PHF8 is essential for NEPC because not only is PHF8 highly expressed in NEPC but also animals without Phf8 failed to develop NEPC. Mechanistically, PHF8 transcriptionally upregulates FOXA2 by demethylating and removing the repressive histone markers on the promoter region of the FOXA2 gene, and the upregulated FOXA2 subsequently regulates the expression of genes involved in NEPC development. Since both PHF8 and FOXA2 are highly expressed in NEPC tissues from patients or patient-derived xenografts, the levels of PHF8 and FOXA2 can either individually or in combination serve as NEPC biomarkers and targeting either PHF8 or FOXA2 could be potential therapeutic strategies for NEPC treatment. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Primitive small cell carcinoma of the prostate. Case report and revision of the literature

A Caucasian man 84 years old was admitted to our Department for acute renal failure secondary to severe bilateral hydronephrosis; moreover, the patient referred chronic fatigue and was anuric from two days. Serum creatinine and PSA values were equal to 9.6 mg/dl and 4.8 ng/ml and digital rectal examination was highly suspicious for prostate cancer. In emergency, the patient underwent bilateral application of percutaneous renal nephrostomies to restore kidney function and, after three days, was submitted to ultrasound-guided extended transperineal biopsy; the histology showed the presence of a prostatic small cell carcinoma (SCC) fulfilling the World Health Organization criteria. The patient underwent clinical staging including chest and abdominal computed tomography evaluation and total body scan that did not demonstrated distant metastases and/or others primitive tumors; in addition, cystoscopy and urinary cytology were negative. The patient underwent multidisciplinary evaluation, but he died 20 days from the diagnosis for progressive clinical worsening (physical and cognitive impairments) before beginning oncological treatment. In conclusion, primitive SCC represents a very rare cancer provided of poor prognosis; only the execution of prostate biopsy combined with an accurate specimen analysis allow to make the correct diagnosis and therapeutic treatment.

Neuroendocrine and Aggressive-Variant Prostate Cancer

In prostate cancer, neuroendocrine (NE) differentiation may rarely present de novo or more frequently arises following hormonal therapy in patients with castration-resistant prostate cancer (CRPC). Its distinct phenotype is characterized by an aggressive clinical course, lack of responsiveness to hormonal therapies and poor prognosis. Importantly, a subset of CRPC patients exhibits an aggressive-variant disease with very similar clinical and molecular characteristics to small-cell prostate cancer (SCPC) even though tumors do not have NE differentiation. This aggressive-variant prostate cancer (AVPC) also shares the sensitivity of SCPC to platinum-based chemotherapy albeit with short-lived clinical benefit. As optimal treatment strategies for AVPC remain elusive, currently ongoing research efforts aim to enhance our understanding of the biology of this disease entity and improve treatment outcomes for our patients. This review is an overview of our current knowledge on prostate cancer with NE differentiation and AVPC, with a focus on their clinical characteristics and management, including available as well as experimental therapeutic strategies.

Paratesticular tumors. A clinicopathological study from a single tertiary hospital in North India

OBJECTIVE

Paratesticular tumors (PTT) are rare and form a heterogenous group, ranging from benign to malignant high grade sarcomas. This study was undertaken to describe the clinicopathological spectrum of PTTs received over a 20-year period.

METHODS

All primary and secondary PTTs diagnosed from 2000 to 2019 in the pathology department of a tertiary care hospital in North India were retrospectively reviewed. Gross, histopathological features and immunohistochemistry (IHC) findings were correlated with clinical details.

RESULTS

A total of 169 intra-scrotal tumors were diagnosed during the study period, out of which there were 30 PTTs (in 27 patients) comprising 17.75%. Age range was 4 to 85 years (median 58 years). Benign PTTs were the commonest (n = 21, 70%), followed by metastasis to the paratesticular region (n = 6, 20%) and then primary malignant PTTs (n = 3, 10%). The commonest benign PTT was lipoma (n = 16, 76.19%), followed by adenomatoid tumor (n = 3, 14.28%) with one case each (4.76%) of cellular angiofibroma and hemangioma. Among primary malignant PTT, there were two cases of rhabdomyosarcoma, and one case of biphasic malignant mesothelioma. Metastatic tumors included four cases of prostatic adenocarcinoma, and one case each of pancreatic signet ring cell carcinoma and clear cell renal cell carcinoma.

CONCLUSION

PTTs show a wide clinicopathological spectrum. Benign PTTs are commoner than malignant PTTs. Meticulous grossing and histopathological examination supplemented by IHC is essential for an accurate diagnosis of this heterogenous class of tumors, which influences the role of adjuvant therapy and patient prognosis.

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.

Neuroendocrine differentiation in usual-type prostatic adenocarcinoma: Molecular characterization and clinical significance

BACKGROUND

Small cell neuroendocrine (NE) carcinomas of the prostate classically lose androgen receptor (AR) expression, may harbor loss of the RB1, TP53, and PTEN tumor suppressor genes, and are associated with a poor prognosis. However usual-type adenocarcinomas may also contain areas of NE differentiation, and in this context the molecular features and biological significance are less certain.

METHODS

We examined the molecular phenotype and oncologic outcomes of primary prostate adenocarcinomas with ≥5% NE differentiation (≥5% chromogranin A-positive NE cells in any given tumor spot on tissue microarray) using three independent study sets: a set of tumors with paneth cell-like NE differentiation (n = 26), a retrospective case-cohort of intermediate- and high-risk patients enriched for adverse outcomes (n = 267), and primary tumors from a retrospective series of men with eventual castration-resistant metastatic prostate cancer (CRPC) treated with abiraterone or enzalutamide (n = 55).

RESULTS

Benign NE cells expressed significantly lower quantified AR levels compared with paired benign luminal cells (P < .001). Similarly, paneth-like NE carcinoma cells or carcinoma cells expressing chromogranin A expressed significantly lower quantified AR levels than paired non-NE carcinoma cells (P < .001). Quantified ERG protein expression, was also lower in chromogranin A-labeled adenocarcinoma cells compared with unlabeled cells (P < .001) and tumors with NE differentiation showed lower gene expression scores for AR activity compared with those without. Despite evidence of lower AR signaling, adenocarcinomas with NE differentiation did not differ by prevalence of TP53 missense mutations, or PTEN or RB1 loss, compared with those without NE differentiation. Finally, NE differentiation was not associated with time to metastasis in intermediate- and high-risk patients (P = .6 on multivariate analysis), nor with progression-free survival in patients with CRPC treated with abiraterone or enzalutamide (P = .9).

CONCLUSION

NE differentiation in usual-type primary prostate adenocarcinoma is a molecularly and clinically distinct form of lineage plasticity from that occurring in small cell NE carcinoma.

Increased nuclear factor I/B expression in prostate cancer correlates with AR expression

BACKGROUND

Most prostate cancers express androgen receptor (AR), and our previous studies have focused on identifying transcription factors that modify AR function. We have shown that nuclear factor I/B (NFIB) regulates AR activity in androgen-dependent prostate cancer cells in vitro. However, the status of NFIB in prostate cancer was unknown.

METHODS

We immunostained a tissue microarray including normal, hyperplastic, prostatic intraepithelial neoplasia, primary prostatic adenocarcinoma, and castration-resistant prostate cancer tissue samples for NFIB, AR, and synaptophysin, a marker of neuroendocrine differentiation. We interrogated publically available data sets in cBioPortal to correlate NFIB expression and AR and neuroendocrine prostate cancer (NEPCa) activity scores. We analyzed prostate cancer cell lines for NFIB expression via Western blot analysis and used nuclear and cytoplasmic fractionation to assess where NFIB is localized. We performed co-immunoprecipitation studies to determine if NFIB and AR interact.

RESULTS

NFIB increased in the nucleus and cytoplasm of prostate cancer samples versus matched normal controls, independent of Gleason score. Similarly, cytoplasmic AR and synaptophysin increased in primary prostate cancer. We observed strong NFIB staining in primary small cell prostate cancer. The ratio of cytoplasmic-to-nuclear NFIB staining was predictive of earlier biochemical recurrence in prostate cancer, once adjusted for tumor margin status. Cytoplasmic AR was an independent predictor of biochemical recurrence. There was no statistically significant difference between NFIB and synaptophysin expression in primary and castration-resistant prostate cancer, but cytoplasmic AR expression was increased in castration-resistant samples. In primary prostate cancer, nuclear NFIB expression correlated with cytoplasmic NFIB and nuclear AR, while cytoplasmic NFIB correlated with synaptophysin, and nuclear and cytoplasmic AR. In castration-resistant prostate cancer samples, NFIB expression correlated positively with an AR activity score, and negatively with the NEPCa score. In prostate cancer cell lines, NFIB exists in several isoforms. We observed NFIB predominantly in the nuclear fraction of prostate cancer cells with increased cytoplasmic expression seen in castration-resistant cell lines. We observed an interaction between AR and NFIB through co-immunoprecipitation experiments.

CONCLUSION

We have described the expression pattern of NFIB in primary and castration-resistant prostate cancer and its positive correlation with AR. We have also demonstrated AR interacts with NFIB.

Specificities of small cell neuroendocrine prostate cancer: Adverse prognostic value of TTF1 expression

OBJECTIVES

To determine whether small cell neuroendocrine prostate cancers (NEPCa) emerging after anti-androgen treatments are different from the rarest cases diagnosed de novo, and to identify effective predictive markers.

MATERIAL AND METHODS

The expression of neuroendocrine markers, androgen receptor (AR) and androgen-regulated genes, as well as markers of aggressiveness, were analyzed by immunohistochemistry on a tissue microarray containing samples of 30 sNEPCa, either pure or admixed with conventional PCa, and including 14 cases diagnosed de novo and 16 cases subsequent to prior androgen deprivation.

RESULTS

Chromogranin A is a better marker of NE differentiation than synaptophysin in post-treatment NEPCa, with 94% and 44% of positive tumors, respectively, while both markers are equally expressed in de novo cases. Despite the acquisition of a NE phenotype, more than half of NEPCa expressed AR and the androgen-regulated gene NKX3.1, more frequently in cases admixed with conventional PCa. TTF1 staining, present in half of NEPCa, was associated with loss of androgen-regulated genes and with markers of aggressiveness, including increased proliferation, Zeb1 expression and PTEN loss. In multivariate analysis, only TTF1 expression was significantly associated with shorter overall survival.

CONCLUSION

These results suggest the persistence of androgen signaling in a number of NEPCa cases, and the interest of TTF1 staining as a predictive biomarker.

Expression of novel neuroendocrine marker insulinoma-associated protein 1 (INSM1) in genitourinary high-grade neuroendocrine carcinomas: An immunohistochemical study with specificity analysis and comparison to chromogranin, synaptophysin, and CD56

Confirmation of genitourinary high-grade neuroendocrine carcinomas (GU-HGNECs) often requires immunohistochemical staining. Here we evaluated a novel neuroendocrine marker, insulinoma-associated protein 1 (INSM1), in GU-HGNECs with comparison to chromogranin, synaptophysin and CD56. Immunohistochemical expression of INSM1, chromogranin, synaptophysin, and CD56 was evaluated in 39 GU-HGNECs using full tissue sections [4 in kidney, 28 in urinary bladder, and 7 in prostate; 31 small cell carcinomas (SmCCs), 6 large cell neuroendocrine carcinomas (LCNECs), 2 mixed SmCC-LCNECs]. In 33 SmCCs/components, INSM1 showed similar sensitivity (93.9 %) to chromogranin (87.8 %), synaptophysin (93.9 %) and CD56 (87.8 %), and stained a similar percentage of tumor cells (52 %) to chromogranin (49 %) and CD56 (52 %), but lower than synaptophysin (87 %) (p < 0.0001). In 8 LCNECs/components, INSM1 is similar to chromogranin, synaptophysin or CD56 in sensitivity (62.5 %, 62.5 %, 75 %, 62.5 %, respectively) and the mean percentage of positively stained tumor cells (21 %, 44 %, 48 %, 37 %, respectively). INSM1 is more sensitive for SmCCs than LCNECs (93.9 % vs. 62.5 %, p = 0.015). INSM1 showed 97.4 % specificity upon analyzing 273 genitourinary non-neuroendocrine tumors on tissue microarrays. Our study indicates that INSM1 is a sensitive marker for genitourinary HGNECs with high specificity. For genitourinary SmCCs, INSM1 shows similar sensitivity to chromogranin, synaptophysin and CD56 but stains a lower percentage of tumor cells than synaptophysin. For genitourinary LCNECs, INSM1 showed similar sensitivity to chromogranin, synaptophysin and CD56. INSM1 is more sensitive for genitourinary SmCCs than LCNECs. Our result and literature review indicate that whether INSM1 is more sensitive than conventional neuroendocrine markers for HGNECs depends on the tumor primary sites.

Neuroendocrine cells of prostate cancer: biologic functions and molecular mechanisms

Prostate cancer (PCa) is a major health risk for older men worldwide. Existing systemic therapies mostly target androgen receptor (AR). Although treatments are initially effective, the disease always recurs. A potential mechanism for the treatment failure is that PCa contains, in addition to the AR-positive luminal type tumor cells, a small component of neuroendocrine (NE) cells. The function of NE cells in PCa remains poorly understood, and one important characteristic of these cells is their lack of expression of AR and resistance to hormonal therapy. In addition, many patients develop the more aggressive small-cell neuroendocrine carcinoma (SCNC) after hormonal therapy. Although this clinical phenomenon of disease transformation from adenocarcinoma to SCNC is well established, the cell of origin for SCNC remains unclear. Recently, loss of function of Rb and TP53 and amplification and overexpression of MYCN and Aurora A kinase have been identified as important biomarkers and potential disease drivers. In this article, we systematically review the histology of normal prostate and prostate cancer including the main histologic types: adenocarcinoma and SCNC. We also review the findings from many studies using cellular and animal models as well as human specimens that attempt to understand the molecular mechanisms of treatment failure, disease progression, and tumor transformation from adenocarcinoma to SCNC.

Small extracellular vesicles modulated by αVβ3 integrin induce neuroendocrine differentiation in recipient cancer cells

The ability of small extracellular vesicles (sEVs) to reprogram cancer cells is well established. However, the specific sEV components able to mediate aberrant effects in cancer cells have not been characterized. Integrins are major players in mediating sEV functions. We have previously reported that the αVβ3 integrin is detected in sEVs of prostate cancer (PrCa) cells and transferred into recipient cells. Here, we investigate whether sEVs from αVβ3-expressing cells affect tumour growth differently than sEVs from control cells that do not express αVβ3. We compared the ability of sEVs to stimulate tumour growth, using sEVs isolated from PrCa C4-2B cells by iodixanol density gradient and characterized with immunoblotting, nanoparticle tracking analysis, immunocapturing and single vesicle analysis. We incubated PrCa cells with sEVs and injected them subcutaneously into nude mice to measure in vivo tumour growth or analysed in vitro their anchorage-independent growth. Our results demonstrate that a single treatment with sEVs shed from C4-2B cells that express αVβ3, but not from control cells, stimulates tumour growth and induces differentiation of PrCa cells towards a neuroendocrine phenotype, as quantified by increased levels of neuroendocrine markers. In conclusion, the expression of αVβ3 integrin generates sEVs capable of reprogramming cells towards an aggressive phenotype.

Telomere lengths differ significantly between small-cell neuroendocrine prostate carcinoma and adenocarcinoma of the prostate

Small-cell neuroendocrine carcinoma (SCNC) of the prostate is an aggressive subtype with frequent TP53 mutation and RB1 inactivation; however, the molecular phenotype remains an area of investigation. Here, we compared telomere lengths in prostatic SCNC and usual-type prostatic adenocarcinoma (AdCa). We studied 32 cases of prostatic SCNC (including 11 cases with concurrent AdCa) and 347 cases of usual-type AdCa on tissue microarrays. Telomere lengths in tumor cells were qualitatively compared with those in normal cells using a telomere-specific fluorescence in situ hybridization assay. ERG, PTEN, and TP53 status were assessed in a proportion of cases using genetically validated immunohistochemistry protocols. Clinicopathological and molecular characteristics of cases were compared between the telomere groups using the chi-square test.A significantly higher proportion of prostatic SCNC cases (50%, 16/32) showed normal/long telomeres compared with AdCa cases (11%, 39/347; P < 0.0001). In 82% (9/11) of cases with concurrent SCNC and AdCa, the paired components were concordant for telomere length status. Among AdCa cases, the proportion of cases with normal/long telomeres significantly increased with increasing tumor grade group (P = 0.01) and pathologic stage (P = 0.02). Cases with normal/long telomeres were more likely to be ERG positive (P = 0.04) and to have TP53 missense mutation (P = 0.01) than cases with short telomeres.Normal or long telomere lengths are significantly more common in prostatic SCNC than in AdCa and are similar between concurrent SCNC and AdCa tumors, supporting a common origin. Among AdCa cases, longer telomere lengths are significantly associated with high-risk pathologic and molecular features.

Morphologic, Molecular and Clinical Features of Aggressive Variant Prostate Cancer

The term aggressive variant prostate cancer (AVPCa) refers to androgen receptor (AR)-independent anaplastic forms of prostate cancer (PCa), clinically characterized by a rapidly progressive disease course. This involves hormone refractoriness and metastasis in visceral sites. Morphologically, AVPCa is made up of solid sheets of cells devoid of pleomorphism, with round and enlarged nuclei with prominent nucleoli and slightly basophilic cytoplasm. The cells do not show the typical architectural features of prostatic adenocarcinoma and mimic the undifferentiated carcinoma of other organs and locations. The final diagnosis is based on the immunohistochemical expression of markers usually seen in the prostate, such as prostate-specific membrane antigen (PSMA). A subset of AVPCa can also express neuroendocrine (NE) markers such as chromogranin A, synaptophysin and CD56. This letter subset represents an intermediate part of the spectrum of NE tumors which ranges from small cell to large cell carcinoma. All such tumors can develop following potent androgen receptor pathway inhibition. This means that castration-resistant prostate cancer (CRPCa) transdifferentiates and becomes a treatment-related NE PCa in a clonally divergent manner. The tumors that do not show NE differentiation might harbor somatic and/or germline alterations in the DNA repair pathway. The identification of these subtypes has direct clinical relevance with regard to the potential benefit of platinum-based chemotherapy, poly (ADP-ribose) polymerase inhibitors and likely further therapies.

The Calcium-Sensing Receptor is A Marker and Potential Driver of Neuroendocrine Differentiation in Prostate Cancer

The mechanisms underlying neuroendocrine (NE) differentiation in prostate cancer (PCa) remain mostly uncharacterized. Since a deregulated calcium homeostasis has been reported in neuroendocrine prostate cancer (NEPC), we explored herein the link between NE differentiation and the calcium-sensing receptor (CaSR). CaSR expression was evaluated by immunohistochemistry-together with NE markers-on tissue microarrays containing samples of normal prostate, localized PCa, metastatic castration resistant PCa (MCRPC) and NEPC. In prostate tissues, we observed a strong association between CaSR and chromogranin expression. Both markers were strongly expressed in all cases of NEPC and co-expression was confirmed by double immunostaining. In MCRPC, the expression of CaSR was significantly associated with shorter overall survival. The involvement of CaSR in NE differentiation was evaluated in PCa cell lines. Inhibition of CaSR led to decrease the expression of neuronal (NSE, βtubulinIII) and NE (chromogranin, synaptophysin) markers in the NE PCa cell line NCI-H660. A decrease of neuronal and NE markers was also observed in siCaSR-transfected PC3 and 22RV1 cells, respectively, whereas CaSR activation increased both NSE and synaptophysin expression in PC3 cells. These results strongly suggest that CaSR is a marker and a driver of NE differentiation in PCa and emphasize the potential of CaSR directed therapy for NEPC patients.

Insulinoma-associated protein 1 (INSM1): a potential biomarker and therapeutic target for neuroendocrine tumors

BACKGROUND

Insulinoma-associated protein 1 (INSM1), a transcriptional regulator with a zinc-finger DNA-binding domain, has been validated as a cytoplasmic marker for neuroendocrine differentiation of tumor cells. Next to its abundant expression in the fetal pancreas, it is expressed in brain tumors, pheochromocytomas, medullary thyroid carcinomas, insulinomas and pituitary and small-cell lung carcinomas. INSM1 is not expressed in normal adult tissues and/or most non-neuroendocrine tumors. It regulates various downstream signaling pathways, including the Sonic Hedgehog, PI3K/AKT, MEK/ERK1/2, ADK, p53, Wnt, histone acetylation, LSD1, cyclin D1, Ascl1 and N-Myc pathways. Although INSM1 appears to be a subtle and specific biomarker for neuroendocrine tumors, its role in tumor development has remained unclear.

CONCLUSIONS

Here, we highlight INSMI expression, as well as its diagnostic significance and use as a therapeutic target in various neuroendocrine tumors. Targeting signaling pathways or gene expression alterations associated with INSM1 expression may be instrumental for the design of novel therapeutic strategies for neuroendocrine tumors.

Immunohistochemistry-based assessment of androgen receptor status and the AR-null phenotype in metastatic castrate resistant prostate cancer

BACKGROUND

Molecular and immunohistochemistry-based profiling of prostatic adenocarcinoma has revealed frequent Androgen Receptor (AR) gene and protein alterations in metastatic disease. This includes an AR-null non-neuroendocrine phenotype of metastatic castrate resistant prostate cancer which may be less sensitive to androgen receptor signaling inhibitors. This AR-null non-neuroendocrine phenotype is thought to be associated with TP53 and RB1 alterations. Herein, we have correlated molecular profiling of metastatic castrate resistant prostate cancer with AR/P53/RB immunohistochemistry and relevant clinical correlates.

DESIGN

Twenty-seven cases of metastatic castrate resistant prostate cancer were evaluated using histopathologic examination to rule out neuroendocrine differentiation. A combination of a hybridization exon-capture next-generation sequencing-based assay (n = 26), fluorescence in situ hybridization for AR copy number status (n = 16), and immunohistochemistry for AR (n = 27), P53 (n = 24) and RB (n = 25) was used to profile these cases.

RESULTS

Of 27 metastatic castrate resistant prostate cancer cases, 17 had AR amplification and showed positive nuclear expression of AR by immunohistochemistry. Nine cases lacked AR copy number alterations using next-generation sequencing/fluorescence in situ hybridization. A subset of these metastatic castrate resistant prostate cancer cases demonstrated the AR-null phenotype by immunohistochemistry (five cases and one additional case where next-generation sequencing failed). Common co-alterations in these cases involved the TP53, RB1, and PTEN genes and all these patients received prior therapy with androgen receptor signaling inhibitors (abiraterone and/or enzalutamide).

CONCLUSIONS

Our study suggests that AR immunohistochemistry may distinguish AR-null from AR-expressing cases in the metastatic setting. AR-null status informs clinical decision-making regarding continuation of therapy with androgen receptor signaling inhibitors and consideration of other treatment options. This might be a relevant and cost-effective diagnostic strategy when there is limited access and/or limited tumor material for molecular testing.

Small Cell Carcinoma of the Prostate: A Case Report and Review of the Literature

Small cell carcinoma of the prostate (SCCP) is a rare malignancy that is considered a lethal entity of prostate cancer. Once it is diagnosed, patients characteristically experience an aggressive clinical course with poor overall survival rates, which unfortunately still holds even with modern treatments. In this report, we discuss the case of a 63-year-old African American male who initially presented to the hospital with an elevated prostate-specific antigen (PSA) level of 9.41 ng/mL and was found to have locally extensive SCCP. After one cycle of chemotherapy, the patient's symptoms worsened, and his disease continued to progress with an increased metastatic burden. In a matter of just a few months, the patient’s disease progressed from a locally advanced entity to a diffusely metastatic one, showcasing the true aggressive nature of this disease. Through an extensive literature review, this case report also sheds further light on SCCP's histological characteristics, its apparent differences from adenocarcinoma of the prostate, and its aggressive nature even through treatment.

MUC1-C regulates lineage plasticity driving progression to neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is an aggressive malignancy with no effective targeted therapies. The oncogenic MUC1-C protein is overexpressed in castration-resistant prostate cancer (CRPC) and NEPC, but its specific role is unknown. Here, we demonstrate that upregulation of MUC1-C in androgen-dependent PC cells suppresses androgen receptor (AR) axis signaling and induces the neural BRN2 transcription factor. MUC1-C activates a MYC→BRN2 pathway in association with induction of MYCN, EZH2 and NE differentiation markers (ASCL1, AURKA and SYP) linked to NEPC progression. Moreover, MUC1-C suppresses the p53 pathway, induces the Yamanaka pluripotency factors (OCT4, SOX2, KLF4 and MYC) and drives stemness. Targeting MUC1-C decreases PC self-renewal capacity and tumorigenicity, suggesting a potential therapeutic approach for CRPC and NEPC. In PC tissues, MUC1 expression associates with suppression of AR signaling and increases in BRN2 expression and NEPC score. These results highlight MUC1-C as a master effector of lineage plasticity driving progression to NEPC.

Diagnostic, prognostic and predictive parameters in prostate cancer

Prostate cancer (CP) is the most common malignancy in men in America, while it is the second most common in Europe. It is responsible for about 10% of cancer deaths in the same population. It is clinically manifested in various forms, from slow-growing to aggressive forms with pronounced metastatic potential. Diagnosis is made by a well-defined algorithm, which begins with the determination of serum prostate specific antigen values and ends with prostate biopsy as the "gold standard". Pathohistological diagnostic criterias are based on architectural, cytoplasmic, nuclear and characteristics of intraluminal structures, as well as periacinar cleftings, which are deffined as helpfull diagnostic criteria of undoubted importance. Prognostic and predictive parameters are classified into three categories. Some of them are an integral part of routine pathohistologicat report, while others are considered as the diagnostic process progresses. Modern knowledge introduces biomarkers into the everyday practice of personalized medicine, especially when is necessary to treat prostate cancer patients.

BMI1 is directly regulated by androgen receptor to promote castration-resistance in prostate cancer

B lymphoma Mo-MLV insertion region 1 (BMI1) has been reported to be an oncoprotein. BMI1 represses tumor suppressors to promote cell proliferation, epithelial-mesenchymal transition (EMT), and cancer progression. Although it is known that the expression of BMI1 is increased in many cancer types, the mechanism of BMI1 upregulation is not yet clear. We performed integrative analysis for 3 sets of prostate cancer (PCa) genomic data, and found that BMI1 and androgen receptor (AR) were positively correlated, suggesting that AR might regulate BMI1. Next, we showed that dihydrotestosterone (DHT) upregulated both mRNA and protein levels of BMI1 and that BMI1 was increased in castration-resistant prostate cancer (CRPC) from both human patients and a mouse xenograph model. We further identified an AR binding site in the promoter/enhancer region of BMI1, and confirmed BMI1 as the direct target of AR using gene-editing technology. We also demonstrated that high expression of BMI1 is critical for the development of castration-resistance. Our data also suggest that BMI1-specific inhibitors could be an effective treatment of CRPC.

Comparative analysis of TTF-1 binding DNA regions in small-cell lung cancer and non-small-cell lung cancer

Thyroid transcription factor-1 (TTF-1, encoded by the NKX2-1 gene) is highly expressed in small-cell lung carcinoma (SCLC) and lung adenocarcinoma (LADC), but how its functional roles differ between SCLC and LADC remains to be elucidated. Here, we compared the genome-wide distributions of TTF-1 binding regions and the transcriptional programs regulated by TTF-1 between NCI-H209 (H209), a human SCLC cell line, and NCI-H441 (H441), a human LADC cell line, using chromatin immunoprecipitation-sequencing (ChIP-seq) and RNA-sequencing (RNA-seq). TTF-1 binding regions in H209 and H441 cells differed by 75.0% and E-box motifs were highly enriched exclusively in the TTF-1 binding regions of H209 cells. Transcriptome profiling revealed that TTF-1 is involved in neuroendocrine differentiation in H209 cells. We report that TTF-1 and achaete-scute homolog 1 (ASCL1, also known as ASH1, an E-box binding basic helix-loop-helix transcription factor, and a lineage-survival oncogene of SCLC) are coexpressed and bound to adjacent sites on target genes expressed in SCLC, and cooperatively regulate transcription. Furthermore, TTF-1 regulated expression of the Bcl-2 gene family and showed antiapoptotic function in SCLC. Our findings suggest that TTF-1 promotes SCLC growth and contributes to neuroendocrine and antiapoptotic gene expression by partly coordinating with ASCL1.

A Limited-Versus-Extensive Staging Strategy for Small Cell Prostate Cancer

INTRODUCTION

Small cell prostate cancer (SCPC) is a rare histologic subtype of prostate cancer, for which the optimal staging strategy remains unclear.

METHOD

The Surveillance, Epidemiology, and End Results database was used to analyze the incidence and outcomes of SCPC between the years 2004 through 2016. Limited-stage SCPC (LS-SCPC) was defined as SCPC without any metastasis regardless of local invasion. Extensive stage SCPC (ES-SCPC) was defined as any metastasis to lymph nodes and/or to distant organs.

RESULT

A total of 403 SCPC patients were included in the study cohort, accounting for 0.056% of all prostate cancer cases (n=719,655). Of the 358 patients with known metastasis status, 275 (76.8%) patients had ES-SCPC, whereas 83 (23.2%) patients had LS-SCPC. LS-SCPC was associated with better overall survival (17 vs. 9 mo, P<0.001) and disease-specific survival (25 vs. 10 mo, P<0.001) compared with ES-SCPC. All LS-SCPC patients had a similar overall survival regardless of T stage. Similarly, all ES-SCPC patients had similar outcomes regardless of metastasis sites. High prostate-specific antigen (PSA) is paradoxically associated with superior outcome in both localized stage patients (PSA≥4 vs. PSA<4, 19 vs. 10 mo, P=0.002) and extensive stage patients (PSA≥20 vs. PSA<20, 13 vs. 9 mo, P=0.02). Multivariate analysis of treatment showed that chemotherapy was associated with improved survival in ES-SCPC with hazard ratio of 0.52.

CONCLUSION

Similar to small cell lung cancer, SCPC can be staged into LS-SCPC or ES-SCPC. The binary staging system correlates well with prognosis.

Clinical features of neuroendocrine prostate cancer

BACKGROUND

Neuroendocrine prostate cancer (NEPC) is an aggressive variant of prostate cancer that may arise de novo or in patients previously treated with hormonal therapies for prostate adenocarcinoma as a mechanism of resistance. Despite being important to recognise, the clinical features of NEPC are poorly defined and could help guide when to perform a biopsy to look for NEPC histologic transformation.

METHODS

We reviewed baseline, treatment and outcome data of 87 patients with metastatic prostate cancer and tumour biopsy confirming NEPC histology. Forty-seven (54.0%) NEPC cases presented de novo, and 40 (46.0%) were therapy-related (t-NEPC). Thirty-six (41.4%) were classified as pure small-cell carcinoma, and 51 (58.6%) demonstrated mixed features with both small-cell carcinoma and adenocarcinoma present. Genomic data were available for 47 patients.

RESULTS

The median age at time of NEPC was 68.1 years, median prostate-specific antigen (PSA) was 1.20 ng/ml (0.14 ng/mL small-cell carcinoma, 1.55 ng/mL mixed carcinoma) and sites of metastases included bone (72.6%), lymph node (47.0%), and viscera (65.5%). Median time from adenocarcinoma to t-NEPC diagnosis was 39.7 months (range, 24.5-93.8) with a median of two lines of prior systemic therapy. Platinum chemotherapy was used to treat 57.5% of patients, with a median progression-free survival of 3.9 months. Small-cell carcinoma was associated with worse overall survival (OS) than mixed histology (8.9 months from NEPC diagnosis versus 26.1 months, P < 0.001). Median OS of de novo NEPC was shorter than that of t-NEPC (16.8 months from prostate cancer diagnosis versus 53.5 months, P = 0.043). An average PSA rise per month of ≤0.7 ng/ml before t-NEPC; elevated lactate dehydrogenase levels, RB1 and TP53 loss and liver metastases were poor prognostic features.

CONCLUSIONS

We describe the clinical features of a cohort of patients with NEPC. These characteristics may inform future diagnostic strategies.

Morphologic Spectrum of Neuroendocrine Tumors of the Prostate: An Updated Review

CONTEXT.—

The incidence of neuroendocrine tumors of the prostate increases after hormonal therapy. Neuroendocrine tumors possess a broad spectrum of morphologic features and pose challenges in the pathologic diagnosis and clinical management of patients.

OBJECTIVE.—

To present a brief updated summary of neuroendocrine tumors of the prostate with an overview of their histopathologic and immunohistochemical profiles and differential diagnoses.

DATA SOURCES.—

Literature review, personal experience in the daily practice of pathologic diagnosis, and laboratory research.

CONCLUSIONS.—

Our understanding of neuroendocrine tumors of the prostate classification and diagnosis continues to evolve. These advances benefit the risk stratification and management of prostate cancer.

Neuroendocrine Differentiation of Prostate Cancer-An Intriguing Example of Tumor Evolution at Play

Our understanding of neuroendocrine prostate cancer (NEPC) has assumed a new perspective in light of the recent advances in research. Although classical NEPC is rarely seen in the clinic, focal neuroendocrine trans-differentiation of prostate adenocarcinoma occurs in about 30% of advanced prostate cancer (PCa) cases, and represents a therapeutic challenge. Even though our knowledge of the mechanisms that mediate neuroendocrine differentiation (NED) is still evolving, the role of androgen deprivation therapy (ADT) as a key driver of this phenomenon is increasingly becoming evident. In this review, we discuss the molecular, cellular, and therapeutic mediators of NED, and emphasize the role of the tumor microenvironment (TME) in orchestrating the phenotype. Understanding the role of the TME in mediating NED could provide us with valuable insights into the plasticity associated with the phenotype, and reveal potential therapeutic targets against this aggressive form of PCa.

TCF4 induces enzalutamide resistance via neuroendocrine differentiation in prostate cancer

In treating patients with castration resistant prostate cancer (CRPC), enzalutamide, the second-generation androgen receptor (AR) antagonist, is an accepted standard of care. However, clinical benefits are limited to a median time of 4.8 months because resistance inevitably emerges. To determine the mechanism of treatment resistance, we carried out a RNA sequence analysis and found increased expression levels of neuroendocrine markers in the enzalutamide-resistant LNCaP human prostate cancer (CaP) cell line when compared to the parental cell line. Subsequent studies demonstrated that Transcription Factor-4 (TCF4), a transcription factor implicated in WNT signaling, mediated neuroendocrine differentiation (NED) in response to enzalutamide treatment and was elevated in the enzalutamide-resistant LNCaP. In addition, we observed that PTHrP mediated enzalutamide resistance in tissue culture and inducible TCF4 overexpression resulted in enzalutamide-resistance in a mouse xenograft model. Finally, small molecule inhibitors of TCF4 or PTHrP partially reversed enzalutamide resistance in CaP cells. When tissues obtained from men who died of metastatic CaP were examined, a positive correlation was found between the expression levels of TCF4 and PTHrP. Taken together, the current results indicate that TCF4 induces enzalutamide resistance via NED in CaP.

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

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

Utility of NKX3.1 Immunostaining in the Detection of Metastatic Prostatic Carcinoma on Fine-Needle Aspiration Smears

OBJECTIVES

NK3 homeobox 1 (NKX3.1) has been increasingly used to diagnose metastatic prostatic carcinoma in histologic samples. However, its utility and reliability in cytologic direct smears have not been studied.

METHODS

A total of 59 fine-needle aspiration (FNA) cases with a definitive diagnosis of metastatic carcinoma from the prostate were included. The cases were grouped based on different Gleason score in their corresponding primary tumors and morphologic variants. For each case, tumor cells were immunostained with NKX3.1, prostate-specific antigen (PSA), and prostatic acid phosphatase (PAP) on cell-transferred smears.

RESULTS

NKX3.1 was strongly and diffusely positive in all 40 metastatic prostatic adenocarcinomas, including those with ductal features, but negative for the 19 small cell carcinoma (SmCC) cases. NKX3.1 had a better detection rate than PSA (13/50, 26%) and PAP (0/47, 0%).

CONCLUSIONS

NKX3.1 immunostaining on FNA smears is highly reliable for detecting metastatic prostatic carcinomas of conventional and ductal types but not for SmCC.

Patterns of care and outcomes in small cell carcinoma of the prostate: A national cancer database analysis

BACKGROUND

Small cell carcinoma (SCC) of the prostate is a rare, aggressive disease. Evidence is limited; however, the current standard of care is chemotherapy. The benefit of local treatment modalities is unknown.

METHODS

We queried the National Cancer Database identifying all SCC/neuroendocrine cases of the prostate, excluding those with unknown nodal or metastatic status, unknown treatment, or those not receiving chemotherapy. Overall survival (OS) was calculated using Kaplan-Meier curves. Multivariable Cox proportional hazards model was used to identify factors associated with survival. A further subgroup analysis was performed on the utility of local therapy on survival in the nonmetastatic setting.

RESULTS

Our final cohort included 657 patients with a median age of 68. Most patients had positive lymph nodes (60.1%) and metastatic disease (70.0%). Median survival was 12 months (95% confidence interval [95% CI], 11.1-13.3 months) with a median follow-up of 11.8 months. Metastatic disease, age greater than or equal to 70, omission of androgen deprivation therapy (ADT), and lower income (P < .05 for all) were all associated with reduced OS. Patients with prostate-specific antigen (PSA) greater than or equal to 33 ng/mL and those receiving ADT had better survival (P < .05). Those with nonmetastatic disease were more likely to undergo prostatectomy and/or prostatic/pelvic radiation (P < .0001). Prostatic/pelvic radiation in the nonmetastatic setting was associated with longer survival (P = .02). Though well powered, our study is limited by the selection bias inherent to all observational studies, despite the statistical methods utilized to reduce this effect.

CONCLUSIONS

Although chemotherapy is the mainstay of treatment, radiation to the prostate/pelvis may be beneficial in the nonmetastatic setting. In addition to chemotherapy, ADT may benefit patients with an elevated PSA.

Treatment-emergent neuroendocrine prostate cancer: molecularly driven clinical guidelines

An increasingly recognized mechanism of prostate cancer resistance is the transdifferentiation from adenocarcinoma to treatment-emergent neuroendocrine prostate cancer (t-NEPC), an extremely aggressive malignancy. The incidence of t-NEPC has been increasing in recent years, in part due to novel treatments that target the androgen receptor pathway. While clinicians historically had very few options for t-NEPC detection and treatment, recent research has uncovered key diagnostic tools and therapeutic targets that can be translated into improved patient care. In this article, we will outline the clinical features of t-NEPC and its molecular pathogenesis. Importantly, we will also discuss recently uncovered molecularly based strategies aimed at improving the diagnosis and treatment of t-NEPC. Finally, we will propose a unified algorithm that integrates clinical and molecular information for the clinical management of t-NEPC.

[Neuroendocrine prostate cancer]

Neuroendocrine prostate cancer (NEPC) mostly occurs as a treatment-emergent adaptive response under the pressure of intensive androgen deprivation treatment (t-NEPC). Approximately 30-40% of patients with metastatic castration-resistant prostate cancer (mCRPC) also have neuroendocrine involvement. In contrast primary small cell prostate cancer is very rare (<1%). A t‑NEPC should be clinically suspected in patients who have particularly aggressive mCRPC but a disproportionately low prostate-specific antigen (PSA) level and elevated neuroendocrine tumor markers, such as chromogranin A and neuron-specific enolase. The initial Gleason score was shown to be an independent factor correlated to the risk of development of t‑NEPC. Treatment is oriented to that of small cell lung cancer. In patients with negative PSA levels, chemotherapy with cisplatin and etoposide is the first line treatment, for which response rates in the range of 30-60% with a median survival time of usually less than 1 year can be achieved. In patients with much higher serum PSA levels, chemotherapy with carboplatin plus docetaxel should be considered.

[Prostate pathology recommendations from the Uropathology working group of the Spanish Society of Pathology]

These guidelines from the uropathology working group of the Spanish Society of Pathology (SEAP) are based on the European and ISUP 2015 recommendations and those of the College of American Pathologists, as well as the latest WHO 2016, TNM (AJCC) 2017 classifications. They include recommendations for specimen sampling, macro- and microscopic examination and immunohistochemistry. Gleason patterns are specified: Gleason pattern 3 includes hyperplastic, atrophic and microcystic glands, while pattern 4 includes all cribriform or glomeruloid glands. The Gleason score in prostatectomy specimens may change; if a tertiary pattern occurs in more than 5% of the tumour, it becomes a secondary pattern. In both biopsies and prostatectomy specimens, if the Gleason score is 7, the percentage of pattern 4 should be stated. Gleason scoring in tumor variants and special situations should also be specified. These recommendations should be adapted according to the resources available.

68Ga-PSMA-PET/CT for the evaluation of liver metastases in patients with prostate cancer

Background

The purpose of this study was to evaluate the imaging properties of hepatic metastases in ⁶⁸Ga-PSMA positron emission tomography (PET) in patients with prostate cancer (PC).

Methods

⁶⁸Ga-PSMA-PET/CT scans of PC patients available in our database were evaluated retrospectively for liver metastases. Metastases were identified using ⁶⁸Ga-PSMA-PET, CT, MRI and follow-up scans. Different parameters including, maximum standardized uptake values (SUV_max) of the healthy liver and liver metastases were assessed by two- and three-dimensional regions of interest (2D/3D ROI).

Results

One hundred three liver metastases in 18 of 739 PC patients were identified. In total, 80 PSMA-positive (77.7%) and 23 PSMA-negative (22.3%) metastases were identified. The mean SUV_max of PSMA-positive liver metastases was significantly higher than that of the normal liver tissue in both 2D and 3D ROI (p ≤ 0.05). The mean SUV_max of PSMA-positive metastases was 9.84 ± 4.94 in 2D ROI and 10.27 ± 5.28 in 3D ROI; the mean SUV_max of PSMA-negative metastases was 3.25 ± 1.81 in 2D ROI and 3.40 ± 1.78 in 3D ROI, and significantly lower than that of the normal liver tissue (p ≤ 0.05). A significant (p ≤ 0.05) correlation between SUV_max in PSMA-positive liver metastases and both size (ρ_Spearman = 0.57) of metastases and PSA serum level (ρ_Spearman = 0.60) was found.

Conclusions

In ⁶⁸Ga-PSMA-PET, the majority of liver metastases highly overexpress PSMA and is therefore directly detectable. For the analysis of PET images, it has to be taken into account that also a significant portion of metastases can only be detected indirectly, as these metastases are PSMA-negative.

ZBTB46, SPDEF, and ETV6: Novel Potential Biomarkers and Therapeutic Targets in Castration-Resistant Prostate Cancer

Prostate cancer (PCa) is the second most common killer among men in Western countries. Targeting androgen receptor (AR) signaling by androgen deprivation therapy (ADT) is the current therapeutic regime for patients newly diagnosed with metastatic PCa. However, most patients relapse and become resistant to ADT, leading to metastatic castration-resistant PCa (CRPC) and eventually death. Several proposed mechanisms have been proposed for CRPC; however, the exact mechanism through which CRPC develops is still unclear. One possible pathway is that the AR remains active in CRPC cases. Therefore, understanding AR signaling networks as primary PCa changes into metastatic CRPC is key to developing future biomarkers and therapeutic strategies for PCa and CRPC. In the current review, we focused on three novel biomarkers (ZBTB46, SPDEF, and ETV6) that were demonstrated to play critical roles in CRPC progression, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) drug resistance, and the epithelial-to-mesenchymal transition (EMT) for patients treated with ADT or AR inhibition. In addition, we summarize how these potential biomarkers can be used in the clinic for diagnosis and as therapeutic targets of PCa.

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.

Essential Updates in Grading, Morphotyping, Reporting, and Staging of Prostate Carcinoma for General Surgical Pathologists

CONTEXT.—

Within this decade, several important updates in prostate cancer have been presented through expert international consensus conferences and influential publications of tumor classification and staging.

OBJECTIVE.—

To present key updates in prostate carcinoma.

DATA SOURCES.—

The study comprised a review of literature and our experience from routine and consultation practices.

CONCLUSIONS.—

Grade groups, a compression of the Gleason system into clinically meaningful groups relevant in this era of active surveillance and multidisciplinary care management for prostate cancer, have been introduced. Refinements in the Gleason patterns notably result in the contemporarily defined Gleason score 6 cancers having a virtually indolent behavior. Grading of tertiary and minor higher-grade patterns in radical prostatectomy has been clarified. A new classification for prostatic neuroendocrine tumors has been promulgated, and intraductal, microcystic, and pleomorphic giant cell carcinomas have been officially recognized. Reporting the percentage of Gleason pattern 4 in Gleason score 7 cancers has been recommended, and data on the enhanced risk for worse prognosis of cribriform pattern are emerging. In reporting biopsies for active surveillance criteria-based protocols, we outline approaches in special situations, including variances in sampling or submission. The 8th American Joint Commission on Cancer TNM staging for prostate cancer has eliminated pT2 subcategorization and stresses the importance of nonanatomic factors in stage groupings and outcome prediction. As the clinical and pathology practices for prostate cancer continue to evolve, it is of utmost importance that surgical pathologists become fully aware of the new changes and challenges that impact their evaluation of prostatic specimens.

Prostate-specific markers to identify rare prostate cancer cells in liquid biopsies

Despite improvements in early detection and advances in treatment, patients with prostate cancer continue to die from their disease. Minimal residual disease after primary definitive treatment can lead to relapse and distant metastases, and increasing evidence suggests that circulating tumour cells (CTCs) and bone marrow-derived disseminated tumour cells (BM-DTCs) can offer clinically relevant biological insights into prostate cancer dissemination and metastasis. Using epithelial markers to accurately detect CTCs and BM-DTCs is associated with difficulties, and prostate-specific markers are needed for the detection of these cells using rare cell assays. Putative prostate-specific markers have been identified, and an optimized strategy for staining rare cancer cells from liquid biopsies using these markers is required. The ideal prostate-specific marker will be expressed on every CTC or BM-DTC throughout disease progression (giving high sensitivity) and will not be expressed on non-prostate-cancer cells in the sample (giving high specificity). Some markers might not be specific enough to the prostate to be used as individual markers of prostate cancer cells, whereas others could be truly prostate-specific and would make ideal markers for use in rare cell assays. The goal of future studies is to use sensitive and specific prostate markers to consistently and reliably identify rare cancer cells.

The Bone Microenvironment in Prostate Cancer Metastasis

The propensity of prostate cancer cells to seed the skeleton and then progress into clinically relevant metastatic tumors is widely recognized and a major cause of morbidity and mortality for patients. The natural history of prostate adenocarcinoma most frequently begins with a tumor diagnosed at a localized stage, which is successfully treated by surgical and/or radiation therapy modalities. A relevant percentage of patients are clinically cured but approximately 20-30% will develop biochemical signs of recurrence, which respond to the inhibition of androgen receptor (AR) signaling by hormone-deprivation and receptor antagonists, before the inevitable transition into castration-resistant prostate cancer (CRPC). This stage simultaneously presents with or is rapidly followed by secondary tumors, which involve the skeleton in more than 90% of cases (mCRPC). While generalization in clinical practice is always unwise, it is indisputable that bone-metastatic prostate cancer is virtually incurable. Decades of research have revealed that the tissue microenvironment provided by the bone marrow is as important as the cell-autonomous features of tumor cells in fostering the right conditions that lead to establishment and progression of metastatic tumors in the skeleton.

Metastatic prostate cancer remains incurable, why?

Metastatic prostate cancer patients present in two ways-with already disseminated disease at the time of presentation or with disease recurrence after definitive local therapy. Androgen deprivation therapy is given as the most effective initial treatment to patients. However, after the initial response, almost all patients will eventually progress despite the low levels of testosterone. Disease at this stage is termed castration resistant prostate cancer (CRPC). Before 2010, the taxane docetaxel was the first and only life prolonging agent for metastatic CRPC (mCRPC). The last decade has witnessed robust progress in CRPC therapeutics development. Abiraterone, enzalutamide, apalutamide and sipuleucel-T have been evaluated as first- and second-line agents in mCRPC patients, while cabazitaxel was approved as a second-line treatment. Radium-223 dichloride was approved in symptomatic patients with bone metastases and no known visceral metastases pre- and post-docetaxel. However, despite significant advances, mCRPC remains a lethal disease. Both primary and acquired resistance have been observed in CRPC patients treated by these new agents. It could be solely cell intrinsic or it is possible that the clonal heterogeneity in treated tumors may result from the adaptive responses to the selective pressures within the tumor microenvironment. The aim of this review is to list current treatment agents of CRPC and summarize recent findings in therapeutic resistance mechanisms.

Genitourinary Pathology Reporting Parameters Most Relevant to the Medical Oncologist

Pathologic variables play an important role in prognostication in urologic malignancies. Histologic subtype, histologic grade, and anatomic extent of disease (pathologic tumor and nodal staging) influence treatment decisions in both the adjuvant and metastatic settings. This article discusses treatment paradigms for the most common urologic malignancies, followed by the evidence base to support the relationship between pathologic assessment and decision making by the medical oncologist.

Rare Pelvic Malignant Tumors in Adults: Treatment Features and Clinical Outcome in Nonmetastatic Disease (Single Institution Experience)

BACKGROUND

Nearly 200 cancers repertories are rare, and more than 20% are pelvic neoplasia. Diagnosis and treatment are challenging, even in reference centers, and survival is influenced by the aggressiveness of certain histologies and absence of a standard of care.

PATIENTS AND METHODS

The authors report the results of a retrospective analysis of patients that attended the Institute of Oncology, Bucharest, between 2004 and 2015, for nonmetastatic pelvic malignant tumor treatment and follow-up. The outcomes are compared between the rare and common histology groups.

RESULTS

Of the 60 cases analyzed, 17 patients (28.33%) bore a rare tumor, 33 (55%) were women, and the median age was 59 years. The majority was concerned by bladder (41.66%, 25 patients) and cervix (23.33%, 14 patients) neoplasms. For a median follow-up of 27.5 months, relapse was registered in 27 patients (45%), of whom 9 (33.33%) were from the rare group (53% of this subpopulation). The highest relapse rates were recorded in patients with rare bladder tumors (66.7%, 4 patients) compared with 42.1% (8 patients) in the common group (p = 0.294) and in prostate localization (66.7%, 2 patients) compared with 16.7% (1 patient) (p = 0.134). Estimated median relapse-free survival (RFS) was 60, 12 months in the rare group and 67 months for common tumors.

CONCLUSIONS

In nonmetastatic rare pelvic tumor patients, the outcome was found to be poorer than in those concerned by common histologies stratified by organ. A higher rate of relapse and the lowest median RFS were observed in bladder and prostatic cancers.

Evolving concepts in prostatic neuroendocrine manifestations: from focal divergent differentiation to amphicrine carcinoma

Prostatic neuroendocrine manifestations encompass a heterogeneous spectrum of morphologic entities. In the era of evidence-based and precision-led treatment, distinction of biologically relevant clinical manifestations expanded the evolving clinical role of pathologists. Recent observations on the occurrence of hormone therapy-induced aggressive prostatic cancers with neuroendocrine features have triggered the need to refine the spectrum and nomenclature of prostatic neuroendocrine manifestations. Although the morphologic assessment still remains the basis of the diagnostic workup of prostatic neoplasms, the application of ancillary biomarkers is crucial in the accurate classification of such presentations. This review provides a diagnostic roadmap for the practicing pathologist by reviewing the characteristic morphologic, immunohistochemical, and molecular correlates of various faces of prostatic neuroendocrine manifestations.

[Neuroendocrine prostate cancer]

Neuroendocrine prostate cancer (NEPC) mostly occurs as a treatment-emergent adaptive response under the pressure of intensive androgen deprivation treatment (t-NEPC). Approximately 30-40% of patients with metastatic castration-resistant prostate cancer (mCRPC) also have neuroendocrine involvement. In contrast primary small cell prostate cancer is very rare (<1%). A t‑NEPC should be clinically suspected in patients who have particularly aggressive mCRPC but a disproportionately low prostate-specific antigen (PSA) level and elevated neuroendocrine tumor markers, such as chromogranin A and neuron-specific enolase. The initial Gleason score was shown to be an independent factor correlated to the risk of development of t‑NEPC. Treatment is oriented to that of small cell lung cancer. In patients with negative PSA levels, chemotherapy with cisplatin and etoposide is the first line treatment, for which response rates in the range of 30-60% with a median survival time of usually less than 1 year can be achieved. In patients with much higher serum PSA levels, chemotherapy with carboplatin plus docetaxel should be considered.

Proteogenomic Characterization of Patient-Derived Xenografts Highlights the Role of REST in Neuroendocrine Differentiation of Castration-Resistant Prostate Cancer

PURPOSE

An increasing number of castration-resistant prostate cancer (CRPC) tumors exhibit neuroendocrine (NE) features. NE prostate cancer (NEPC) has poor prognosis, and its development is poorly understood.Experimental Design: We applied mass spectrometry-based proteomics to a unique set of 17 prostate cancer patient-derived xenografts (PDX) to characterize the effects of castration in vivo, and the proteome differences between NEPC and prostate adenocarcinomas. Genome-wide profiling of REST-occupied regions in prostate cancer cells was correlated to the expression changes in vivo to investigate the role of the transcriptional repressor REST in castration-induced NEPC differentiation.

RESULTS

An average of 4,881 proteins were identified and quantified from each PDX. Proteins related to neurogenesis, cell-cycle regulation, and DNA repair were found upregulated and elevated in NEPC, while the reduced levels of proteins involved in mitochondrial functions suggested a prevalent glycolytic metabolism of NEPC tumors. Integration of the REST chromatin bound regions with expression changes indicated a direct role of REST in regulating neuronal gene expression in prostate cancer cells. Mechanistically, depletion of REST led to cell-cycle arrest in G₁, which could be rescued by p53 knockdown. Finally, the expression of the REST-regulated gene secretagogin (SCGN) correlated with an increased risk of suffering disease relapse after radical prostatectomy.

CONCLUSIONS

This study presents the first deep characterization of the proteome of NEPC and suggests that concomitant inhibition of REST and the p53 pathway would promote NEPC. We also identify SCGN as a novel prognostic marker in prostate cancer.

ZIP9 but not the androgen receptor mediates testosterone-induced migratory activity of metastatic prostate cancer cells

LNCaP cells are derived from a metastatic lesion of human prostate adenocarcinoma. They express the classical androgen receptor (AR) and ZIP9, a Zn²⁺ transporter that also binds testosterone and mediates signaling by interacting with G-proteins. Our results show that LNCaP cells respond to testosterone by mobilizing their migratory machinery. Their exposure to testosterone triggers the formation of lamellipodia, reorganization of the actin cytoskeleton, phosphorylation of focal adhesion kinase (FAK) at Tyr925 and of paxillin at Tyr118, expression of matrix metalloproteinase 2 (MMP-2), and cell migration. Silencing ZIP9 expression by means of siRNA does not affect the responsiveness of the classical AR to testosterone; however, it prevents all of the testosterone effects described above: formation of lamellipodia cannot be induced, stimulation of FAK or paxillin phosphorylation or MMP-2 expression is prevented, and cell migration does not take place in the absence of ZIP9. The data presented show that testosterone/ZIP9 interactions might have not only physiological but also pathophysiological relevance. The fact that the migratory machinery of a metastatic prostate cancer cell line is activated exclusively through testosterone/ZIP9 and not through testosterone/AR interactions suggests that targeting specific inhibition of testosterone/ZIP9-mediated events might help in developing new therapeutic strategies against androgen-induced progression of prostate cancer.

Loss of PSMA Expression in Non-neuroendocrine Dedifferentiated Acinar Prostate Cancer

The introduction of tracers targeting the prostate-specific membrane antigen (PSMA) has revolutionized PET imaging of acinar prostate adenocarcinoma. In general, an increasing PSMA expression is assumed with increasing dedifferentiation. Whereas loss of PSMA expression has been reported in case of neuroendocrine dedifferentiation, we present a patient with acinar prostate adenocarcinoma with a loss of PSMA expression after chemotherapy on PET/CT and in histological and immunohistochemical analyses. All tissue samples indicated the retention of acinar features but no expression of neuroendocrine markers (NSE, synaptophysin, chromogranin, and CD56), corresponding to nonelevated serum NSE.