LuCaP Prostate Cancer Patient-Derived Xenografts Reflect the Molecular Heterogeneity of Advanced Disease an--d Serve as Models for Evaluating Cancer Therapeutics.

BACKGROUND: Metastatic prostate cancer is a common and lethal disease for which there are no therapies that produce cures or long-term durable remissions. Clinically relevant preclinical models are needed to increase our understanding of biology of this malignancy and to evaluate new agents that might provide effective treatment. Our objective was to establish and characterize patient-derived xenografts (PDXs) from advanced prostate cancer (PC) for investigation of biology and evaluation of new treatment modalities. METHODS: Samples of advanced PC obtained from primary prostate cancer obtained at surgery or from metastases collected at time of death were implanted into immunocompromised mice to establish PDXs. Established PDXs were propagated in vivo. Genomic, transcriptomic, and STR profiles were generated. Responses to androgen deprivation and docetaxel in vivo were characterized. RESULTS: We established multiple PDXs (LuCaP series), which represent the major genomic and phenotypic features of the disease in humans, including amplification of androgen receptor, PTEN deletion, TP53 deletion and mutation, RB1 loss, TMPRSS2-ERG rearrangements, SPOP mutation, hypermutation due to MSH2/MSH6 genomic aberrations, and BRCA2 loss. The PDX models also exhibit variation in intra-tumoral androgen levels. Our in vivo results show heterogeneity of response to androgen deprivation and docetaxel, standard therapies for advanced PC, similar to the responses of patients to these treatments. CONCLUSIONS: The LuCaP PDX series reflects the diverse molecular composition of human castration-resistant PC and allows for hypothesis-driven cause-and-effect studies of mechanisms underlying treatment response and resistance. Prostate 77: 654-671, 2017. © 2017 The Authors. The Prostate Published by Wiley Periodicals, Inc.

Characterizing the molecular features of ERG-positive tumors in primary and castration resistant prostate cancer.

BACKGROUND: The TMPRSS2-ERG gene fusion is detected in approximately half of primary prostate cancers (PCa) yet the prognostic significance remains unclear. We hypothesized that ERG promotes the expression of common genes in primary PCa and metastatic castration-resistant PCa (CRPC), with the objective of identifying ERG-associated pathways, which may promote the transition from primary PCa to CRPC. METHODS: We constructed tissue microarrays (TMA) from 127 radical prostatectomy specimens, 20 LuCaP patient-derived xenografts (PDX), and 152 CRPC metastases obtained immediately at time of death. Nuclear ERG was assessed by immunohistochemistry (IHC). To characterize the molecular features of ERG-expressing PCa, a subset of IHC confirmed ERG+ or ERG- specimens including 11 radical prostatectomies, 20 LuCaP PDXs, and 45 CRPC metastases underwent gene expression analysis. Genes were ranked based on expression in primary PCa and CRPC. Common genes of interest were targeted for IHC analysis and expression compared with biochemical recurrence (BCR) status. RESULTS: IHC revealed that 43% of primary PCa, 35% of the LuCaP PDXs, and 18% of the CRPC metastases were ERG+ (12 of 48 patients [25%] had at least one ERG+ metastasis). Based on gene expression data and previous literature, two proteins involved in calcium signaling (NCALD, CACNA1D), a protein involved in inflammation (HLA-DMB), CD3 positive immune cells, and a novel ERG-associated protein, DCLK1 were evaluated in primary PCa and CRPC metastases. In ERG+ primary PCa, a weak association was seen with NCALD and CACNA1D protein expression. HLA-DMB association with ERG was decreased and CD3 cell number association with ERG was changed from positive to negative in CRPC metastases compared to primary PCa. DCLK1 was upregulated at the protein level in unpaired ERG+ primary PCa and CRPC metastases (P = 0.0013 and P < 0.0001, respectively). In primary PCa, ERG status or expression of targeted proteins was not associated with BCR-free survival. However, for primary PCa, ERG+DCLK1+ patients exhibited shorter time to BCR (P = 0.06) compared with ERG+DCLK1- patients. CONCLUSIONS: This study examined ERG expression in primary PCa and CRPC. We have identified altered levels of inflammatory mediators associated with ERG expression. We determined expression of DCLK1 correlates with ERG expression and may play a role in primary PCa progression to metastatic CPRC. Prostate 76:810-822, 2016. © 2016 Wiley Periodicals, Inc.

Prostate Cancer Expression Profiles of Cytoplasmic ERß1 and Nuclear ERß2 are Associated with Poor Outcomes following Radical Prostatectomy.

PURPOSE: Existing data regarding the expression of estrogen receptors (ERs) and prostate cancer outcomes have been limited. We evaluated the relationship of expression profiles of ERß subtypes and the ER GPR30 (G-protein-coupled receptor-30) with patient factors at diagnosis and outcomes following radical prostatectomy. MATERIALS AND METHODS: Tissue microarrays constructed using samples from 566 men with long-term clinical followup were analyzed by immunohistochemistry targeting ERß1, ERß2, ERß5 and GPR30. An experienced pathologist scored receptor distribution and staining intensity. Tumor staining characteristics were evaluated for associations with patient characteristics, recurrence-free survival and prostate cancer specific mortality following radical prostatectomy. RESULTS: Prostate cancer cells had unique receptor subtype staining patterns. ERß1 demonstrated predominantly nuclear localization while ERß2, ERß5 and GPR30 were predominantly cytoplasmic. After controlling for patient factors intense cytoplasmic ERß1 staining was independently associated with time to recurrence (HR 1.7, 95% CI 1.1-2.6, p = 0.01) and prostate cancer specific mortality (HR 6.6, 95% CI 1.8-24.9, p = 0.01). Intense nuclear ERß2 staining was similarly independently associated with prostate cancer specific mortality (HR 3.9, 95% CI 1.1-13.4, p = 0.03). Patients with cytoplasmic ERß1 and nuclear ERß2 co-staining had significantly worse 15-year prostate cancer specific mortality than patients with expression of only cytoplasmic ERß1, only nuclear ERß2 and neither ER (16.4%, 4.3%, 0.0% and 2.0 %, respectively, p = 0.001). CONCLUSIONS: Increased cytoplasmic ERß1 and nuclear ERß2 expression is associated with worse cancer specific outcomes following radical prostatectomy. These findings suggest that tumor ERß1 and ERß2 staining patterns provide prognostic information on patients treated with radical prostatectomy.

Metformin effects on biochemical recurrence and metabolic signaling in the prostate.

BACKGROUND: Metformin has received considerable attention as a potential anti-cancer agent. Animal and in-vitro prostate cancer (PCa) models have demonstrated decreased tumor growth with metformin, however the precise mechanisms are unknown. We examine the effects of metformin on PCa biochemical recurrence (BCR) in a large clinical database followed by evaluating metabolic signaling changes in a cohort of men undergoing prostate needle biopsy (PNB). METHODS: Men treated for localized PCa were identified in a comprehensive clinical database between 2001 and 2010. Cox regression was performed to determine association with BCR relative to metformin use. We next identified a separate case-control cohort of men undergoing prostate needle biopsy (PNB) stratified by metformin use. Differences in mean IHC scores were compared with linear regression for phosphorylated IR, IGF-IR, AKT, and AMPK. RESULTS: One thousand seven hundred and thirty four men were evaluated for BCR with mean follow up of 41 months (range 1-121 months). "Ever" metformin use was not associated with BCR (HR 1.12, 0.77-1.65), however men reporting both pre/post-treatment metformin use had a 45% reduction in BCR (HR = 0.55 (0.31-0.96)). For the tissue-based study, 48 metformin users and 42 controls underwent PNB. Significantly greater staining in phosphorylated nuclear (p-IR, p-AKT) and cytoplasmic (p-IR, p-IGF-1R) insulin signaling proteins were seen in patients with PCa detected compared to those with negative PNB (P-values all <0.006). When stratified by metformin use, IGF-1R remained significantly elevated (P = 0.01) in men with PCa detected whereas p-AMPK (P = 0.05) was elevated only in those without PCa. CONCLUSION: Metformin use is associated with reduced BCR after treatment of localized PCa when considering pre-diagnostic and cumulative dosing. In men with cancer detected on PNB, insulin signaling markers were significantly elevated compared to negative PNB patients. The finding of IGF-1R elevation in positive PNBs versus p-AMPK elevation in negative PNBs suggests altered metabolic pathway activation precipitated by metformin use.

Tumour cell survival mechanisms in lethal metastatic prostate cancer differ between bone and soft tissue metastases.

The complexity of survival mechanisms in cancer cells from patients remains poorly understood. To obtain a comprehensive picture of tumour cell survival in lethal prostate cancer metastases, we examined five survival proteins that operate within three survival pathways in a cohort of 185 lethal metastatic prostate metastases obtained from 44 patients. The expression levels of BCL-2, BCL-XL, MCL-1, cytoplasmic survivin, nuclear survivin, and stathmin were measured by immunohistochemistry in a tissue microarray. Simultaneous expression of three or more proteins occurred in 81% of lethal prostate cancer metastases and BCL-2, cytoplasmic survivin and MCL-1 were co-expressed in 71% of metastatic sites. An unsupervised cluster analysis separated bone and soft tissue metastases according to patterns of survival protein expression. BCL-2, cytoplasmic survivin and MCL-1 had significantly higher expression in bone metastases (p < 10(-5)), while nuclear survivin was significantly higher in soft tissue metastases (p = 3 × 10(-14)). BCL-XL overexpression in soft tissue metastases almost reached significance (p = 0.09), while stathmin expression did not (p = 0.28). In addition, the expression of MCL-1 was significantly higher in AR-positive tumours. Neuroendocrine differentiation was not associated with specific survival pathways. These studies show that bone and soft tissue metastases from the same patient differ significantly in expression of a panel of survival proteins and that with regard to survival protein expression, expression is associated with the metastatic site and not the patient. Altogether, this suggests that optimal therapeutic inhibition may require combinations of drugs that target both bone and soft tissue-specific survival pathways.

Investigation of the relationship between prostate cancer and MSMB and NCOA4 genetic variants and protein expression.

Two genome-wide association studies (GWAS) identified the ß-microseminoprotein (MSMB) promoter SNP, rs10993994:C>T, as significantly associated with prostate cancer (PC) risk. Follow-up studies demonstrate that the variant allele directly affects expression of the MSMB-encoded protein, PSP94, and also suggest that it affects mRNA expression levels of an adjacent gene, NCOA4, which is involved in androgen receptor transactivation. In a population-based study of 1,323 cases and 1,268 age-matched controls, we found the NCOA4 SNP, rs7350420:T>C, was associated with a 15% reduction in PC risk, but the association was not significant after adjustment for the rs10993994:C>T genotype. Tumor tissue microarrays of 519 radical prostatectomy patients were used to measure PSP94 and NCOA4 protein expression. Taken together, these data confirm that the rs10993994:C>T variant allele is associated with decreased PSP94 expression, and the association is stronger in tumor compared to normal prostate tissue. No association was observed between rs10993994:C>T and NCOA4 expression, and only moderate associations were seen between two NCOA4 SNPs, rs10761618:T>C and rs7085433:G>A, and NCOA4 protein expression. These data indicate that the increase in PC risk associated with rs10993994:C>T is likely mediated by the variant's effect on PSP94 expression; however, this effect does not extend to NCOA4 in the data presented here.

Characterization of osteoblastic and osteolytic proteins in prostate cancer bone metastases.

BACKGROUND: Approximately 90% of patients who die of Prostate Cancer (PCa) have bone metastases, which promote a spectrum of osteoblastic, osteolytic or mixed bone responses. Numerous secreted proteins have been reported to promote osteoblastic or osteolytic bone responses. We determined whether previously identified and/or novel proteins were associated with the osteoblastic or osteolytic response in clinical specimens of PCa bone metastases. METHODS: Gene expression was analyzed on 14 PCa metastases from 11 patients by microarray profiling and qRT-PCR, and protein expression was analyzed on 33 PCa metastases from 30 patients by immunohistochemistry on highly osteoblastic and highly osteolytic bone specimens. RESULTS: Transcript and protein levels of BMP-2, BMP-7, DKK-1, ET-1, and Sclerostin were not significantly different between osteoblastic and osteolytic metastases. However, levels of OPG, PGK1, and Substance P proteins were increased in osteoblastic samples. In addition, Emu1, MMP-12, and sFRP-1 were proteins identified with a novel role of being associated with either the osteoblastic or osteolytic bone response. CONCLUSIONS: This is the first detailed analysis of bone remodeling proteins in human specimens of PCa bone metastases. Three proteins not previously shown to be involved may have a role in the PCa bone response. Furthermore, our data suggests that the relative expression of numerous, rather than a single, bone remodeling proteins determine the bone response in PCa bone metastases.

A model for the design and construction of a resource for the validation of prognostic prostate cancer biomarkers: the Canary Prostate Cancer Tissue Microarray.

Tissue microarrays (TMAs) provide unique resources for rapid evaluation and validation of tissue biomarkers. The Canary Foundation Retrospective Prostate Tissue Microarray Resource used a rigorous statistical design, quota sampling, a variation of the case-cohort study, to select patients for inclusion in a multicenter, retrospective prostate cancer TMA cohort. The study is designed to definitively validate tissue biomarkers of prostate cancer recurrence after radical prostatectomy. Tissue samples from over 1000 participants treated for prostate cancer with radical prostatectomy between 1995 and 2004 were selected at 6 participating institutions in the United States and Canada. This design captured the heterogeneity of screening and clinical practices in the contemporary North American population. Standardized clinical data were collected in a centralized database. The project has been informative in several respects. The scale and complexity of assembling TMAs with over 200 cases at each of 6 sites involved unanticipated levels of effort and time. Our statistical design promises to provide a model for outcome-based studies where tissue localization methods are applied to high-density TMAs.

Protease-activated receptor 2 signaling upregulates angiogenic growth factors in renal cell carcinoma.

Renal cell carcinoma (RCC) is a highly vascular tumor associated with expression of various angiogenic growth factors. The precise process of how these growth factors are regulated in RCC is not fully understood. Recent evidence suggests that protease activated receptors (PARs), a new family of G-protein coupled receptors, play a crucial role in vascular development and tumor progression through a variety of mechanisms. However, the nature of PAR expression in human RCC tissues and its function in regulating angiogenesis in RCC are largely unknown. In this study, we investigated the expression and function of PAR-2 in RCC. RT-PCR and immunohistochemistry assays show that PAR-2 expression is significantly increased in human RCC tissue compared with the adjacent non-neoplastic kidney tissue. In RCC derived cells, PAR-2 is functional as evidenced by robust signaling through MAP kinases including ERK1/2 and JNK. Furthermore, activation of PAR-2 significantly upregulates several angiogenic cytokines, including interleukin-6 (IL-6), IL-8, monocytes chemotactic protein-1 (MCP-1) and growth-related oncogene (GRO). To our knowledge, this is the first report that characterized PAR-2 expression in RCC tissue and further demonstrated that PAR-2 has a critical role in regulating angiogenesis in RCC.

Enzalutamide-induced and PTH1R-mediated TGFBR2 degradation in osteoblasts confers resistance in prostate cancer bone metastases.

Enzalutamide resistance has been observed in approximately 50% of patients with prostate cancer (PCa) bone metastases. Therefore, there is an urgent need to investigate the mechanisms and develop strategies to overcome resistance. We observed enzalutamide resistance in bone lesion development induced by PCa cells in mouse models. We found that the bone microenvironment was indispensable for enzalutamide resistance because enzalutamide significantly inhibited the growth of subcutaneous C4-2B tumors and the proliferation of C4-2B cells isolated from the bone lesions, and the resistance was recapitulated only when C4-2B cells were co-cultured with osteoblasts. In revealing how osteoblasts contribute to enzalutamide resistance, we found that enzalutamide decreased TGFBR2 protein expression in osteoblasts, which was supported by clinical data. This decrease was possibly through PTH1R-mediated endocytosis. We showed that PTH1R blockade rescued enzalutamide-mediated decrease in TGFBR2 levels and enzalutamide responses in C4-2B cells that were co-cultured with osteoblasts. This is the first study to reveal the contribution of the bone microenvironment to enzalutamide resistance and identify PTH1R as a feasible target to overcome the resistance in PCa bone metastases.

The potential impact of reproducibility of Gleason grading in men with early stage prostate cancer managed by active surveillance: a multi-institutional study.

PURPOSE: We evaluated the reproducibility of Gleason grading as relevant to the clinical treatment of men on active surveillance. MATERIALS AND METHODS: Three sets of digital images of prostatic adenocarcinoma in biopsies were reviewed and assigned Gleason scores by a total of 11 pathologists from 7 institutions. Interobserver and intra-observer reproducibility were assessed for assignment of the highest Gleason pattern (3 vs 4 or higher). We also identified 97 consecutive patients on active surveillance. Prostate biopsy glass slides from 82 of the patients were available for re-review and the frequency of carcinoma requiring the distinction of tangentially sectioned Gleason pattern 3 from 4 was determined. RESULTS: Interobserver reproducibility for classic Gleason patterns was substantial (Light's κ 0.76). Interobserver reproducibility for the histological distinction of tangentially sectioned Gleason pattern 3 from Gleason pattern 4 was only fair (Light's κ 0.27). Intra-observer reproducibility ranged from 65% to 100% (mean 81.5%). Of the 82 patients on active surveillance 61 had carcinoma and 15 (24.5%) had a set of biopsies with at least 1 focus in which the distinction between tangentially sectioned Gleason pattern 3 and poorly formed pattern 4 glands had to be considered. CONCLUSIONS: The reproducibility of grading classic Gleason patterns is high. However, variability in grading occurred when distinguishing between tangentially sectioned pattern 3 glands and the poorly formed gland subset of pattern 4. Developing universally accepted histological and/or molecular criteria to distinguish these patterns and subsequently characterizing their natural history would be useful when treating patients on active surveillance.

Biphasic Squamoid Alveolar Renal Cell Carcinoma of the Kidney Involved by Atypical CD5-Positive B-Cells.

Biphasic squamoid alveolar renal cell carcinoma (BSARCC) is a recently described kidney cancer entity with <60 published cases so far. Some unique features of BSARCC include distinct squamoid and alveolar morphology forming glomeruloid configurations and 2 types of tumor cells with different immunoprofiles. Although the mechanism is unknown, neutrophils and cellular materials engulfed by larger tumor cells (described as "emperipolesis") are observed in all reported cases including the current one. In this article, we report a case of a 70-year-old man who presented with an incidental renal mass during workup for immunoglobulin M monoclonal gammopathy of unknown significance and cold agglutinin autoimmune hemolytic anemia. A detailed pathologic evaluation and immunohistochemical studies revealed BSARCC colliding with atypical CD5+ monoclonal B-cells.

Kallikrein-related peptidase-4 initiates tumor-stroma interactions in prostate cancer through protease-activated receptor-1.

In prostate cancer, the mechanism by which the stromal cells surrounding the cancer epithelium become reactive and overproduce growth factors is unclear. Furthermore, the precise process of how these stromal cells stimulate the cancer epithelium is not fully understood. We recently found that protease-activated receptor-1 (PAR-1) in these reactive stromal cells is upregulated. To investigate the role of PAR-1 in the stromal-epithelial interaction, WPMY-1 stromal myofibroblasts were stimulated with PAR-1 agonists including thrombin and PAR-1 activating peptide. We show that WPMY-1 cells have functional PAR-1 by signaling through ERK1/2. Conditioned media (CM) from PAR-1 agonists-treated WPMY-1 cells stimulate the epithelial LNCaP cells leading to ERK1/2 activation and cell proliferation. Cytokine array analysis of the CM demonstrates that PAR-1 induces stromal cells to release numerous cytokines, of which interleukin 6 (IL-6) is the major factor responsible for mitogenic signaling in LNCaP cells. CM further induces expression of prostate-specific kallikrein-related peptidase-3 (KLK3/PSA) and KLK4 in LNCaP cells via the IL-6 pathway. Moreover, KLK4 functions as a potent agonist of PAR-1 by cleaving the receptor at the proper site on cell surface. KLK4 triggers transmembrane signaling and upregulates IL-6 in WPMY-1 cells through PAR-1. Immunohistochemical analysis indicates that PAR-1 is predominantly expressed in peritumoral stroma while KLK4 is produced exclusively by the epithelial cancer cells. These data provide evidence for a novel double-paracrine mechanism whereby cancer epithelium produces KLK4 to activate PAR-1 in the surrounding stroma, which in-turn releases cytokines (IL-6) that stimulate cancer cells to proliferate and increase production of KLKs.

Protease-activated receptor-1 is upregulated in reactive stroma of primary prostate cancer and bone metastasis.

BACKGROUND: Prostate cancer progression is partly facilitated by tumor-stroma interactions. We recently reported that protease-activated receptors (PAR-1 and PAR-2) are overexpressed in prostate cancer, and PAR-1 expression in peritumoral stroma is associated with biochemical recurrence. However, the nature of PAR expression in prostate tumor microenvironment is not fully understood. We therefore evaluated PAR-1 and PAR-2 expression in primary prostate cancer and bone metastasis. METHODS: PAR-1 and PAR-2 expression in normal, primary prostate cancer and the corresponding bone metastatic tissues were examined by immunohistochemistry, and double-label immunohistochemistry with the use of additional markers. RESULTS: PAR-1 was expressed in peritumoral stroma in the majority of primary cancer tissues (83%). Serial sections and double-label immunohistochemistry determined that these PAR-1 expressing stromal cells were predominantly myofibroblasts, the primary cell type in reactive stroma. Analysis of cancer glands revealed that PAR-1 expression was significantly increased in the reactive stroma around higher Gleason grade cancers. PAR-2 was predominantly expressed in the primary cancer cells as well as smooth muscle cells but not in reactive stroma. In bone metastasis, PAR-1 expression in cancer cells was elevated compared to the primary site from the same patient. In the bone reactive stroma, PAR-1 was present in vascular endothelial cells and fibroblasts, while both PAR-1 and PAR-2 were expressed in osteoblasts and osteoclasts. CONCLUSIONS: In primary prostate cancer and bone metastasis, PAR-1 is upregulated in reactive stroma and PAR-2 is uniformly overexpressed in carcinoma cells, suggesting these receptors may play potentially different roles in prostate cancer development and metastasis.

Association of prostate cancer SLCO gene expression with Gleason grade and alterations following androgen deprivation therapy.

BACKGROUND: SLCO-encoded transporters have been associated with progression to castration-resistant prostate cancer (CRPC) after initiation of androgen deprivation therapy (ADT). Although expressed at lower levels than in CRPC tissues, SLCO-encoded transporters may also play a role in response of primary prostate cancer (PCa) to ADT and biochemical recurrence. METHODS: We systematically explored expression of the 11 human SLCO genes in a large sample of untreated and ADT-treated normal prostate (NP) and primary PCa tissues, including tumors treated with neoadjuvant abiraterone. RESULTS: Transporters with the most recognized role in steroid uptake in PCa, including SLCO2B1 (DHEAS) and 1B3 (testosterone), were consistently detected in primary PCa. SLCO1B3 was nearly 5-fold higher in PCa vs NP with no difference in Gleason 3 vs 4 and no change with ADT. SLCO2B1 was detected at 3-fold lower levels in PCa than NP but was nearly 7-fold higher in Gleason 4 vs Gleason 3 and increased 3-fold following ADT (p < 0.05 for all). CONCLUSIONS: We observed clear differences in SLCO expression in PCa vs NP samples, in Gleason 4 vs Gleason 3 tumors, and in ADT-treated vs untreated tissues. These findings are hypothesis generating due to small sample size, but suggest that baseline and ADT-induced changes in PCa OATP expression may influence steroid uptake and response to ADT, as well as uptake and response to drugs such as abiraterone and docetaxel which are also subject to OATP-mediated transport and are now being routinely combined with ADT in the metastatic castration sensitive setting.

Contribution of Adrenal Glands to Intratumor Androgens and Growth of Castration-Resistant Prostate Cancer.

PURPOSE: Tumor androgens in castration-resistant prostate cancer (CRPC) reflect de novo intratumoral synthesis or adrenal androgens. We used C.B.-17 SCID mice in which we observed adrenal CYP17A activity to isolate the impact of adrenal steroids on CRPC tumors in vivo. EXPERIMENTAL DESIGN: We evaluated tumor growth and androgens in LuCaP35CR and LuCaP96CR xenografts in response to adrenalectomy (ADX). We assessed protein expression of key steroidogenic enzymes in 185 CRPC metastases from 42 patients. RESULTS: Adrenal glands of intact and castrated mice expressed CYP17A. Serum DHEA, androstenedione (AED), and testosterone (T) in castrated mice became undetectable after ADX (all P < 0.05). ADX prolonged median survival (days) in both CRPC models (33 vs. 179; 25 vs. 301) and suppressed tumor steroids versus castration alone (T 0.64 pg/mg vs. 0.03 pg/mg; DHT 2.3 pg/mg vs. 0.23 pg/mg; and T 0.81 pg/mg vs. 0.03 pg/mg, DHT 1.3 pg/mg vs. 0.04 pg/mg; all P ≤ 0.001). A subset of tumors recurred with increased steroid levels, and/or induction of androgen receptor (AR), truncated AR variants, and glucocorticoid receptor (GR). Metastases from 19 of 35 patients with AR positive tumors concurrently expressed enzymes for adrenal androgen utilization and nine expressed enzymes for de novo steroidogenesis (HSD3B1, CYP17A, AKR1C3, and HSD17B3). CONCLUSIONS: Mice are appropriate for evaluating adrenal impact of steroidogenesis inhibitors. A subset of ADX-resistant CRPC tumors demonstrate de novo androgen synthesis. Tumor growth and androgens were suppressed more strongly by surgical ADX than prior studies using abiraterone, suggesting reduction in adrenally-derived androgens beyond that achieved by abiraterone may have clinical benefit. Proof-of-concept studies with agents capable of achieving true "nonsurgical ADX" are warranted.

Assessment of The Bethesda System for Reporting Thyroid Cytopathology.

OBJECTIVES: Long-term follow-up is important for determining performance characteristics of thyroid fine-needle aspiration (FNA). METHODS: Histologic or 3 or more years of clinical follow-up was used to calculate performance characteristics of thyroid FNA before and after implementation of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). The impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) classification was also investigated. RESULTS: Follow-up was obtained for 1,277/1,134 and 1,616/1,393 aspirates/patients (median clinical follow-up, 9.9 and 4.4 years, pre- and post-TBSRTC, respectively). Nondiagnostic, suspicious for follicular neoplasm, and suspicious for malignancy (SFM) diagnoses decreased and benign diagnoses increased post-TBSRTC, while atypical rate remained less than 1%. Negative predictive value for benign nodules and positive predictive value (PPV) for SFM increased significantly. Eleven nodules were reclassified as NIFTP, slightly decreasing PPV/risk of malignancy (ROM). CONCLUSIONS: Appropriate ROM for thyroid FNA can be achieved through application of TBSRTC terminology with minimal use of atypical category.

Cervical Lymph Node Fine-Needle Aspiration and Needle-Wash Thyroglobulin Reflex Test for Papillary Thyroid Carcinoma.

Fine-needle aspiration (FNA) cytology coupled with needle-wash thyroglobulin (FNA-Tg) testing is recommended for cervical lymph node (LN) biopsies in patients with a history of papillary thyroid carcinoma (PTC). However, the procedure has not been standardized with the assay for FNA-Tg testing. A standard operating procedure (SOP) has been generated at our facility for cervical LN FNAs with Tg reflex testing on patients with a history of PTC. The procedure requires FNA cytology to be reviewed first, and all cases not positive for PTC are reflexed for FNA-Tg testing with the Beckman Access thyroglobulin assay. The thyroglobulin cutoff value is ≤ 1.0 ng/mL. From 2016 to 2017, 117 patients, including 71 women and 46 men, were identified as having a history of PTC. Patients' clinical characteristics were collected from medical records. A total of 143 LN biopsies were investigated for these patients. The results show that four out of 11 (36.4%) non-diagnostic LNs and five out of five (100%) atypical/suspicious LNs tested positive for FNA-Tg. Among these nine patients with positive thyroglobulin testing, LN metastases were proven histologically for all nine patients, and two patients were treated with LN ablation. Out of 68 LNs positive for PTC, three had FNA-Tg results. FNA-Tg testing was ordered for unknown reasons on two positive LNs (> 5000 ng/mL thyroglobulin) from one patient. The third LN was tested due to non-classic morphology, and the result was less than the cutoff value. Three patients with negative LN biopsies were tested to have elevated (> 1.0 ng/mL) thyroglobulin levels. One patient (FNA-Tg ng/mL) was proven to have multiple metastatic LNs through follow-up surgery. However, no positive LN was identified for the other two patients who had FNA-Tg level of 4.1 ng/mL and 37 ng/mL respectively. This is likely due to contamination, as these two patients had intact thyroids. In our practice, the FNA-Tg test is a very useful adjunct test to LN FNA specimens with a non-positive diagnosis in patients with a history of PTC. Furthermore, FNA-Tg testing increases diagnostic sensitivity among non-diagnostic and atypical/suspicious LNs. However, FNA-Tg testing should not substitute conventional cytology due to the following reasons: (1) false-negative thyroglobulin lab results; (2) PTC with loss of thyroglobulin expression; (3) LN metastasis from other origins; and (4) false-positive thyroglobulin testing due to blood contamination in patients who are not completely athyrotic.

Ki67 Proliferative Index in Carcinoid Tumors Involving Ovary.

Primary ovarian carcinoid tumors are rare neoplasms that constitute less than 0.1% of all ovarian carcinomas. However, carcinoid tumors metastatic to ovaries are more common. Cell proliferative rate is an important factor in the determination of neuroendocrine tumor prognosis. Limited data are available as regards Ki67 proliferation index in predicting the physiological features of carcinoid tumors involving the ovary. Pathology files of Mayo Clinic Rochester (1995-2014) were searched, and clinical information was collected from medical records. All cases were stained with an antibody against Ki67, and digital analysis was performed with digital imaging analysis. A total of 36 cases (median age 64 years, range 33-83 years), including 9 primary (median age 68 years, range 33-73 years) and 27 metastatic carcinoid cases (median age 64 years, range 36-83 years), were investigated in the current study. Seven out of nine (77.8%) primary ovarian carcinoids are associated with mature teratoma. Twenty two metastatic carcinoids (81.5%) were from the GI tract, four (14.8%) from the pancreas, and one (3.7%) from the posterior thorax location. There was significant difference of Ki67 index between primary (median 2.3%, range, 0.6-8.4%) and metastatic carcinoid tumors (median 9.7%, range, 1.3-46.7%) (p = 0.002). The survival time is much shorter among patients with metastatic carcinoid tumor (median survival 5.8 years) comparing to primary ovarian carcinoid tumor (median 14.2 years) (p = 0.0005). A strong association between Ki67 index and patient survival time was identified (Hazard ratio for 1-percentage point increase 1.11, p = 0.001). Comparing to primary ovarian carcinoid tumor, metastatic carcinoid usually exhibits a higher Ki67 index and a worse outcome.

Androgen Receptor Pathway-Independent Prostate Cancer Is Sustained through FGF Signaling.

Androgen receptor (AR) signaling is a distinctive feature of prostate carcinoma (PC) and represents the major therapeutic target for treating metastatic prostate cancer (mPC). Though highly effective, AR antagonism can produce tumors that bypass a functional requirement for AR, often through neuroendocrine (NE) transdifferentiation. Through the molecular assessment of mPCs over two decades, we find a phenotypic shift has occurred in mPC with the emergence of an AR-null NE-null phenotype. These "double-negative" PCs are notable for elevated FGF and MAPK pathway activity, which can bypass AR dependence. Pharmacological inhibitors of MAPK or FGFR repressed the growth of double-negative PCs in vitro and in vivo. Our results indicate that FGF/MAPK blockade may be particularly efficacious against mPCs with an AR-null phenotype.