Survey of lived experiences and challenges in hepatitis B management and treatment.

Almost 300 million people are living with chronic hepatitis B infection worldwide and most remain undiagnosed and at risk for liver cancer. In 2015 the World Health Organization (WHO) developed guidelines for the prevention, care, and treatment of persons with chronic hepatitis B and in early 2023 began to work on updating these guidelines. In March 2023, a self-administered, anonymous online survey was launched, aiming to identify patient preferences related to the clinical management of hepatitis B including current management, treatment, and care experiences, preferences regarding engagement with providers, and preferences related to simplifying hepatitis B care access. A sample of 560 individuals living with hepatitis B (self-identified as HBsAg positive) from 76 countries completed the survey. Key findings demonstrated that less than half (49%, N = 268) of participants regularly visited a doctor to check the health of their liver (every 6-12 months), with 37% of participants prescribed antiviral medication by a specialist (82%, N = 167) or general practitioner (13%, N = 26). Participants reported not being actively involved in care decision making with their providers (42%, N = 217), with an overwhelming majority wanting to participate in hepatitis B management and treatment choices (85%, N = 435). Participants provided qualitative and quantitative details using open-ended responses within the survey about challenges with medication affordability and receiving care from a knowledgeable provider. Overall findings demonstrated key gaps in care, management, and treatment access related to hepatitis B: identifying these gaps can be used to identify areas for improvement along the care continuum for viral hepatitis. The survey found a need for the comprehensive simplification of clinical management and health care services related to hepatitis B. A thematic analysis of the open-ended survey responses highlighted major overarching themes including the cost and access burdens associated with hepatitis B management and treatment, and challenges in finding knowledgeable providers. Results from this mixed methods survey were used to inform the WHO hepatitis B guidelines update. Efforts should continue to explore public health approaches to address barriers and facilitators to testing, care, and treatment for people with hepatitis B to improve awareness of hepatitis B and access, care, and treatment among patients and providers.

Overexpression of Fibroblast Activation Protein (FAP) in stroma of proliferative inflammatory atrophy (PIA) and primary adenocarcinoma of the prostate.

Fibroblast activation protein (FAP) is a serine protease upregulated at sites of tissue remodeling and cancer that represents a promising therapeutic and molecular imaging target. In prostate cancer, studies of FAP expression using tissue microarrays are conflicting, such that its clinical potential is unclear. Furthermore, little is known regarding FAP expression in benign prostatic tissues. Here we demonstrated, using a novel iterative multiplex IHC assay in standard tissue sections, that FAP was nearly absent in normal regions, but was increased consistently in regions of proliferative inflammatory atrophy (PIA). In carcinoma, FAP was expressed in all cases, but was highly heterogeneous. High FAP levels were associated with increased pathological stage and cribriform morphology. We verified that FAP levels in cancer correlated with CD163+ M2 macrophage density. In this first report to quantify FAP protein in benign prostate and primary tumors, using standard large tissue sections, we clarify that FAP is present in all primary prostatic carcinomas, supporting its potential clinical relevance. The finding of high levels of FAP within PIA supports the injury/regeneration model for its pathogenesis and suggests that it harbors a protumorigenic stroma. Yet, high levels of FAP in benign regions could lead to false positive FAP-based molecular imaging results in clinically localized prostate cancer.

Chromogenic detection of telomere lengths in situ aids the identification of precancerous lesions in the prostate.

BACKGROUND: Telomeres are terminal chromosomal elements that are essential for the maintenance of genomic integrity. The measurement of telomere content provides useful diagnostic and prognostic information, and fluorescent methods have been developed for this purpose. However, fluorescent-based tissue assays are cumbersome for investigators to undertake, both in research and clinical settings. METHODS: A robust chromogenic in situ hybridization (CISH) approach was developed to visualize and quantify telomere content at single cell resolution in human prostate tissues, both frozen and formalin-fixed, paraffin-embedded (FFPE). RESULTS: This new assay (telomere chromogenic in situ hybridization ["Telo-CISH"]) produces permanently stained slides that are viewable with a standard light microscope, thus avoiding the need for specialized equipment and storage. The assay is compatible with standard immunohistochemistry, thereby allowing simultaneous assessment of histomorphology, identification of specific cell types, and assessment of telomere status. In addition, Telo-CISH eliminates the problem of autofluorescent interference that frequently occurs with fluorescent-based methods. Using this new assay, we demonstrate successful application of Telo-CISH to help identify precancerous lesions in the prostate by the presence of markedly short telomeres specifically in the luminal epithelial cells. CONCLUSIONS: In summary, with fewer restrictions on the types of tissues that can be tested, and increased histologic information provided, the advantages presented by this novel chromogenic assay should extend the applicability of tissue-based telomere length assessment in research and clinical settings.

FASN Gene Methylation is Associated with Fatty Acid Synthase Expression and Clinical-genomic Features of Prostate Cancer.

Fatty acid synthase (FASN) catalyzes the synthesis of long-chain saturated fatty acids and is overexpressed during prostatic tumorigenesis, where it is the therapeutic target in several ongoing trials. However, the mechanism of FASN upregulation in prostate cancer remains unclear. Here, we examine FASN gene CpG methylation pattern by InfiniumEPIC profiling and whole-genome bisulfite sequencing across multiple racially diverse primary and metastatic prostate cancer cohorts, comparing with FASN protein expression as measured by digitally quantified IHC assay and reverse phase protein array analysis or FASN gene expression. We demonstrate that the FASN gene body is hypomethylated and overexpressed in primary prostate tumors compared with benign tissue, and FASN gene methylation is significantly inversely correlated with FASN protein or gene expression in both primary and metastatic prostate cancer. Primary prostate tumors with ERG gene rearrangement have increased FASN expression and we find evidence of FASN hypomethylation in this context. FASN expression is also significantly increased in prostate tumors from carriers of the germline HOXB13 G84E mutation compared with matched controls, consistent with a report that HOXB13 may contribute to epigenetic regulation of FASN in vitro. However, in contrast to previous studies, we find no significant association of FASN expression or methylation with self-identified race in models that include ERG status across two independent primary tumor cohorts. Taken together, these data support a potential epigenetic mechanism for FASN regulation in the prostate which may be relevant for selecting patients responsive to FASN inhibitors. SIGNIFICANCE: Here, we leverage multiple independent primary and metastatic prostate cancer cohorts to demonstrate that FASN gene body methylation is highly inversely correlated with FASN gene and protein expression. This finding may shed light on epigenetic mechanisms of FASN regulation in prostate cancer and provides a potentially useful biomarker for selecting patients in future trials of FASN inhibitors.

MYC-driven increases in mitochondrial DNA copy number occur early and persist throughout prostatic cancer progression.

Increased mitochondrial function may render some cancers vulnerable to mitochondrial inhibitors. Since mitochondrial function is regulated partly by mitochondrial DNA copy number (mtDNAcn), accurate measurements of mtDNAcn could help reveal which cancers are driven by increased mitochondrial function and may be candidates for mitochondrial inhibition. However, prior studies have employed bulk macrodissections that fail to account for cell type-specific or tumor cell heterogeneity in mtDNAcn. These studies have often produced unclear results, particularly in prostate cancer. Herein, we developed a multiplex in situ method to spatially quantify cell type-specific mtDNAcn. We show that mtDNAcn is increased in luminal cells of high-grade prostatic intraepithelial neoplasia (HGPIN), is increased in prostatic adenocarcinomas (PCa), and is further elevated in metastatic castration-resistant prostate cancer. Increased PCa mtDNAcn was validated by 2 orthogonal methods and is accompanied by increases in mtRNAs and enzymatic activity. Mechanistically, MYC inhibition in prostate cancer cells decreases mtDNA replication and expression of several mtDNA replication genes, and MYC activation in the mouse prostate leads to increased mtDNA levels in the neoplastic prostate cells. Our in situ approach also revealed elevated mtDNAcn in precancerous lesions of the pancreas and colon/rectum, demonstrating generalization across cancer types using clinical tissue samples.

Convergent alterations in the tumor microenvironment of MYC-driven human and murine prostate cancer.

The tissue microenvironment in prostate cancer is profoundly altered. While such alterations have been implicated in driving prostate cancer initiation and progression to aggressive disease, how prostate cancer cells and their precursors mediate those changes is unclear, in part due to the inability to longitudinally study the disease evolution in human tissues. To overcome this limitation, we performed extensive single-cell RNA-sequencing (scRNA-seq) and rigorous molecular pathology of the comparative biology between human prostate cancer and key time points in the disease evolution of a genetically engineered mouse model (GEMM) of prostate cancer. Our studies of human tissues, with validation in a large external data set, revealed that cancer cell-intrinsic activation of MYC signaling was the top up-regulated pathway in human cancers, representing a common denominator across the well-known molecular and pathological heterogeneity of human prostate cancer. Likewise, numerous non-malignant cell states in the tumor microenvironment (TME), including non-cancerous epithelial, immune, and fibroblast cell compartments, were conserved across individuals, raising the possibility that these cell types may be a sequelae of the convergent MYC activation in the cancer cells. To test this hypothesis, we employed a GEMM of prostate epithelial cell-specific MYC activation in two mouse strains. Cell communication network and pathway analyses suggested that MYC oncogene-expressing neoplastic cells, directly and indirectly, reprogrammed the TME during carcinogenesis, leading to the emergence of cascading cell state alterations in neighboring epithelial, immune, and fibroblast cell types that paralleled key findings in human prostate cancer. Importantly, among these changes, the progression from a precursor-enriched to invasive-cancer-enriched state was accompanied by a cell-intrinsic switch from pro-immunogenic to immunosuppressive transcriptional programs with coinciding enrichment of immunosuppressive myeloid and Treg cells in the immune microenvironment. These findings implicate activation of MYC signaling in reshaping convergent aspects of the TME of prostate cancer as a common denominator across the otherwise well-documented molecular heterogeneity of human prostate cancer.

Club-like cells in proliferative inflammatory atrophy of the prostate.

Club cells are a type of bronchiolar epithelial cell that serve a protective role in the lung and regenerate damaged lung epithelium. Single-cell RNA sequencing (scRNA-seq) of young adult human prostate and urethra identified cell populations in the prostatic urethra and collecting ducts similar in morphology and transcriptomic profile to lung club cells. We further identified club cell-like epithelial cells by scRNA-seq of prostate peripheral zone tissues. Here, we aimed to identify and spatially localize club cells in situ in the prostate, including in the peripheral zone. We performed chromogenic RNA in situ hybridization for five club cell markers (CP, LTF, MMP7, PIGR, SCGB1A1) in a series of (1) nondiseased organ donor prostate and (2) radical prostatectomy specimens from individuals with prostate cancer. We report that expression of club cell genes in the peripheral zone is associated with inflammation and limited to luminal epithelial cells classified as intermediate cells in proliferative inflammatory atrophy (PIA). Club-like cells were enriched in radical prostatectomy specimens compared to nondiseased prostates and associated with high-grade prostate cancer. We previously reported that luminal epithelial cells in PIA can rarely harbor oncogenic TMPRSS2:ERG (ERG+) gene fusions, and we now demonstrate that club cells are present in association with ERG+ PIA that is transitioning to early adenocarcinoma. Finally, prostate epithelial organoids derived from prostatectomy specimens demonstrate that club-like epithelial cells can be established in organoids and are sensitive to anti-androgen-directed treatment in vitro in terms of decreased androgen signaling gene expression signatures compared to basal or hillock cells. Overall, our study identifies a population of club-like cells in PIA and proposes that these cells play an analogous role to that of club cells in bronchiolar epithelium. Our results further suggest that inflammation drives lineage plasticity in the human prostate and that club cells in PIA may be prone to oncogenic transformation. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Predicting Prostate Cancer Molecular Subtype With Deep Learning on Histopathologic Images.

Microscopic examination of prostate cancer has failed to reveal a reproducible association between molecular and morphologic features. However, deep-learning algorithms trained on hematoxylin and eosin (H&E)-stained whole slide images (WSI) may outperform the human eye and help to screen for clinically-relevant genomic alterations. We created deep-learning algorithms to identify prostate tumors with underlying ETS-related gene (ERG) fusions or PTEN deletions using the following 4 stages: (1) automated tumor identification, (2) feature representation learning, (3) classification, and (4) explainability map generation. A novel transformer-based hierarchical architecture was trained on a single representative WSI of the dominant tumor nodule from a radical prostatectomy (RP) cohort with known ERG/PTEN status (n = 224 and n = 205, respectively). Two distinct vision transformer-based networks were used for feature extraction, and a distinct transformer-based model was used for classification. The ERG algorithm performance was validated across 3 RP cohorts, including 64 WSI from the pretraining cohort (AUC, 0.91) and 248 and 375 WSI from 2 independent RP cohorts (AUC, 0.86 and 0.89, respectively). In addition, we tested the ERG algorithm performance in 2 needle biopsy cohorts comprised of 179 and 148 WSI (AUC, 0.78 and 0.80, respectively). Focusing on cases with homogeneous (clonal) PTEN status, PTEN algorithm performance was assessed using 50 WSI reserved from the pretraining cohort (AUC, 0.81), 201 and 337 WSI from 2 independent RP cohorts (AUC, 0.72 and 0.80, respectively), and 151 WSI from a needle biopsy cohort (AUC, 0.75). For explainability, the PTEN algorithm was also applied to 19 WSI with heterogeneous (subclonal) PTEN loss, where the percentage tumor area with predicted PTEN loss correlated with that based on immunohistochemistry (r = 0.58, P = .0097). These deep-learning algorithms to predict ERG/PTEN status prove that H&E images can be used to screen for underlying genomic alterations in prostate cancer.

Progressive Spreading of DNA Methylation in the GSTP1 Promoter CpG Island across Transitions from Precursors to Invasive Prostate Cancer.

Glutathione S-transferase pi 1 (GSTP1) is lowly expressed in normal prostate luminal cells and becomes induced in most proliferative inflammatory atrophy (PIA) lesions. GSTP1 becomes silenced in prostatic intraepithelial neoplasia (PIN) and prostate adenocarcinoma (CaP) via cytosine-phospho-guanine (CpG) island promoter hypermethylation. However, GSTP1 methylation patterns in PIA and PIN, and their relationship to patterns in CaP are poorly understood. We used bisulfite genomic sequencing to examine patterns of GSTP1 promoter CpG island methylation in laser capture microdissected benign, PIA, PIN, and CaP regions from 32 subjects that underwent radical prostatectomy. We analyzed 908 sequence clones across 24 normal epithelium, 37 PIA, 18 PIN, and 23 CaP regions, allowing assessment of 34,863 CpG sites with allelic phasing. Normal and PIA lesions were mostly unmethylated with 0.52 and 1.3% of total CpG sites methylated, respectively. PIN and CaP lesions had greater methylation with 24% and 51% of total CpG sites methylated, respectively. The degree of GSTP1 methylation showed progression from PIA << PIN < CaP. PIN lesions showed more partial methylation compared with CaP lesions. Partially methylated lesions were enriched for methylation changes at AP1 and SP1 transcription factor binding sites. These results demonstrate that methylation density in the GSTP1 CpG island in PIN was intermediate relative to that in normal prostate epithelium/PIA and CaP lesions. These results are consistent with gradual spreading of DNA methylation centered at the SP1/AP1 transcription factor binding sites in precursor lesions, with subsequent spreading of methylation across the entire CpG island in transition to CaP. PREVENTION RELEVANCE: DNA hypermethylation at the GSTP1 promoter progressively spreads from being unmethylated in normal prostate to intermediate levels in precursor lesions to extensive methylation in cancer. This molecular progression of GSTP1 promoter methylation patterns in early prostate carcinogenesis could be useful for identification and interception of prostate cancer precursors.

Chromogenic detection of telomere lengths in situ aids the identification of precancerous lesions in the prostate.

Telomeres are terminal chromosomal elements that are essential for the maintenance of genomic integrity. The measurement of telomere content provides useful diagnostic and prognostic information, and fluorescent methods have been developed for this purpose. However, fluorescent-based tissue assays are cumbersome for investigators to undertake, both in research and clinical settings. Here, a robust chromogenic in situ hybridization (CISH) approach was developed to visualize and quantify telomere content at single cell resolution in human prostate tissues, both frozen and formalin-fixed, paraffin-embedded (FFPE). This new assay ("Telo-CISH") produces permanently stained slides that are viewable with a standard light microscope, thus avoiding the need for specialized equipment and storage. The assay is compatible with standard immunohistochemistry, thereby allowing simultaneous assessment of histomorphology, identification of specific cell types, and assessment of telomere status. In addition, Telo-CISH eliminates the problem of autofluorescent interference that frequently occurs with fluorescent-based methods. Using this new assay, we demonstrate successful application of Telo-CISH to help identify precancerous lesions in the prostate by the presence of markedly short telomeres specifically in the luminal epithelial cells. In summary, with fewer restrictions on the types of tissues that can be tested, and increased histologic information provided, the advantages presented by this novel chromogenic assay should extend the applicability of tissue-based telomere length assessment in research and clinical settings.

MYC-driven increases in mitochondrial DNA copy number occur early and persist throughout prostatic cancer progression.

Increased mitochondrial function may render some cancers vulnerable to mitochondrial inhibitors. Since mitochondrial function is regulated partly by mitochondrial DNA copy number (mtDNAcn), accurate measurements of mtDNAcn could help reveal which cancers are driven by increased mitochondrial function and may be candidates for mitochondrial inhibition. However, prior studies have employed bulk macrodissections that fail to account for cell type-specific or tumor cell heterogeneity in mtDNAcn. These studies have often produced unclear results, particularly in prostate cancer. Herein, we developed a multiplex in situ method to spatially quantify cell type specific mtDNAcn. We show that mtDNAcn is increased in luminal cells of high-grade prostatic intraepithelial neoplasia (HGPIN), is increased in prostatic adenocarcinomas (PCa), and is further elevated in metastatic castration-resistant prostate cancer. Increased PCa mtDNAcn was validated by two orthogonal methods and is accompanied by increases in mtRNAs and enzymatic activity. Mechanistically, MYC inhibition in prostate cancer cells decreases mtDNA replication and expression of several mtDNA replication genes, and MYC activation in the mouse prostate leads to increased mtDNA levels in the neoplastic prostate cells. Our in situ approach also revealed elevated mtDNAcn in precancerous lesions of the pancreas and colon/rectum, demonstrating generalization across cancer types using clinical tissue samples.

Neighborhood disadvantage, health status, and health care utilization after blood or marrow transplant: BMTSS report.

Living in a disadvantaged neighborhood is associated with poor health outcomes. Blood or Marrow Transplant (BMT) survivors remain at risk of chronic health conditions requiring anticipatory management. We hypothesized that among BMT survivors, neighborhood disadvantage was associated with poor self-reported routine health care utilization and health. We leveraged data from BMTSS - a retrospective cohort study examining long-term outcomes among individuals surviving ≥2 y following BMT at three institutions between 1974 and 2014. Participants in this analysis completed the BMTSS survey (sociodemographics; chronic health conditions; time since routine check-up; self-reported health). The Area Deprivation Index (ADI) represented neighborhood disadvantage; this composite indicator of 17 census measures is a percentile rank (0 = least deprived to 100 = most deprived). Multivariable ordered logit regression adjusted for clinical factors and individual-level sociodemographics, modeling associations between ADI, time since routine check-up, and self-reported health. Among 2,857 survivors, median ADI was 24 (interquartile range: 10-46). Adjusting for self-reported individual-level socioeconomic indicators and chronic health conditions, patients in more disadvantaged neighborhoods had higher odds of reporting longer intervals since routine check-up (ORADI_continuous = 1.007, P < .001) and poorer health status (controlling for time since check-up; ORADI_continuous = 1.005, P = .003). Compared with patients living in the least disadvantaged neighborhood (ADI = 1), patients in the most disadvantaged neighborhood (ADI = 100), had twice the odds (ORADI = 1.007^99 = 2.06) of reporting no routine visits and 1.65-times the odds of reporting poor health (ORADI = 1.005^99 = 1.65). In BMT survivors, access to health care and health status are associated with area disadvantage. These findings may inform strategies to address long-term care coordination and retention for vulnerable survivors.

Evaluation of An Inpatient Pharmacy Consult on Discharge Medications in Bariatric Surgery Patients.

PURPOSE: To evaluate the impact of an inpatient pharmacy consult on discharge medications following bariatric surgery. METHODS: A pharmacy consult for discharge medication review for bariatric surgery patients was instituted at an academic medical center. The intervention included conducting a medication history, reviewing home medications for updates post-bariatric surgery, creating and documenting a discharge medication plan, and providing patient education. The impact of the intervention was evaluated by comparing medication classes, doses, and formulations prescribed during the intervention relative to a historical control group. RESULTS: The study included 85 patients who received pharmacist intervention and 167 patients who did not receive pharmacist intervention following bariatric surgery. The prescription of an extended-release medication at discharge in the intervention group was reduced by 19.3% (28.7% vs. 9.4%, p = 0.0005). For patients on hypertension medications, 94.0% had their regimen reduced in the intervention group compared with 37.5% of patients in the control group (p < 0.001). Of patients on insulin at baseline, 87.5% of patients in the intervention group had dose reductions at discharge vs. 66.7% of patients in the control group (p = 0.37). No patients in the intervention group were discharged with oral antihyperglycemic medications or non-insulin injectable medications vs. 33.3% (p = 0.12) and 20.0% (p = 0.47), respectively, in the control group. Readmission rates at 30 days were insignificantly lower in the intervention group (3.5% vs. 4.2%, p = 1). CONCLUSIONS: Clinical pharmacist involvement in the discharge medication reconciliation process for bariatric surgery patients reduced prescribing of unadjusted medication classes, doses, and drug formulations.

Financial Burden in Blood or Marrow Transplantation Survivors During the COVID-19 Pandemic: A BMTSS Report.

PURPOSE: The financial burden experienced by blood or marrow transplant (BMT) survivors during the COVID-19 pandemic remains unstudied. We evaluated the risk for high out-of-pocket medical costs and associated financial burden experienced by BMT survivors and a sibling comparison group during the COVID-19 pandemic. METHODS: This study included 2,370 BMT survivors and 750 siblings who completed the BMT Survivor Study survey during the pandemic. Participants reported employment status, out-of-pocket medical costs, and financial burden. Medical expenses ≥ 10% of the annual household income constituted high out-of-pocket medical costs. Logistic regression identified factors associated with high out-of-pocket medical costs and financial burden. RESULTS: BMT survivors were more likely to incur high out-of-pocket medical costs (11.3% v 3.1%; adjusted odds ratio [aOR], 2.88; 95% CI, 1.84 to 4.50) than the siblings. Survivor characteristics associated with high out-of-pocket medical costs included younger age at study (aORper_year_younger_age, 1.02; 95% CI, 1.00 to 1.03), lower prepandemic annual household income and/or education (< $50,000 US dollars and/or < college graduate: aOR, 1.96; 95% CI, 1.42 to 2.69; reference: ≥ $50,000 in US dollars and ≥ college graduate), > 1 chronic health condition (aOR, 2.82; 95% CI, 2.00 to 3.98), ≥ 1 hospitalization during the pandemic (aOR, 2.11; 95% CI, 1.53 to 2.89), and being unemployed during the pandemic (aOR, 1.52; 95% CI, 1.06 to 2.17). Among BMT survivors, high out-of-pocket medical costs were significantly associated with problems in paying medical bills (aOR, 10.57; 95% CI, 7.39 to 15.11), deferring medical care (aOR, 4.93; 95% CI, 3.71 to 6.55), taking a smaller dose of medication than prescribed (aOR, 4.99; 95% CI, 3.23 to 7.70), and considering filing for bankruptcy (aOR, 3.80; 95% CI, 2.14 to 6.73). CONCLUSION: BMT survivors report high out-of-pocket medical costs, which jeopardizes their health care and may affect health outcomes. Policies aimed at reducing financial burden in BMT survivors, such as expanding access to patient assistance programs, may mitigate the negative health consequences.

Androgen receptor activity in prostate cancer dictates efficacy of bipolar androgen therapy through MYC.

Testosterone is the canonical growth factor of prostate cancer but can paradoxically suppress its growth when present at supraphysiological levels. We have previously demonstrated that the cyclical administration of supraphysiological androgen (SPA), termed bipolar androgen therapy (BAT), can result in tumor regression and clinical benefit for patients with castration-resistant prostate cancer. However, predictors and mechanisms of response and resistance have been ill defined. Here, we show that growth inhibition of prostate cancer models by SPA required high androgen receptor (AR) activity and were driven in part by downregulation of MYC. Using matched sequential patient biopsies, we show that high pretreatment AR activity predicted downregulation of MYC, improved clinical response, and prolonged progression-free and overall survival for patients on BAT. BAT induced strong downregulation of AR in all patients, which is shown to be a primary mechanism of acquired resistance to SPA. Acquired resistance was overcome by alternating SPA with the AR inhibitor enzalutamide, which induced adaptive upregulation of AR and resensitized prostate cancer to SPA. This work identifies high AR activity as a predictive biomarker of response to BAT and supports a treatment paradigm for prostate cancer involving alternating between AR inhibition and activation.

Clonal relationships of adjacent Gleason pattern 3 and Gleason pattern 5 lesions in Gleason Scores 3+5=8 and 5+3=8.

Genomic studies have demonstrated a high level of intra-tumoral heterogeneity in prostate cancer. There is strong evidence suggesting that individual tumor foci can arise as genetically distinct, clonally independent lesions. However, recent studies have also demonstrated that adjacent Gleason pattern (GP) 3 and GP4 lesions can originate from the same clone but follow divergent genetic and morphologic evolution. The clonal relationship of adjacent GP3 and GP5 lesions has thus far not been investigated. Here we analyzed a cohort of 14 cases-11 biopsy and 3 radical prostatectomy specimens-with a Gleason score of 3 + 5 = 8 or 5 + 3 = 8 present in the same biopsy or in a single dominant tumor nodule at radical prostatectomy. Clonal and subclonal relationships between GP3 and GP5 lesions were assessed using genetically validated immunohistochemical assays for ERG, PTEN, and P53. 9/14 (64%) cases showed ERG reactivity in both GP3 and GP5 lesions. Only 1/14 (7%) cases showed a discordant pattern with ERG staining present only in GP3. PTEN expression was lost in 2/14 (14%) cases with perfect concordance between GP5 and GP3. P53 nuclear reactivity was present in 1/14 (7%) case in both GP5 and GP3. This study provides first evidence that the majority of adjacent GP3 and GP5 lesions share driver alterations and are clonally related. In addition, we observed a lower-than-expected rate of PTEN loss in GP5 in the context of Gleason score 3 + 5 = 8 or 5 + 3 = 8 tumors.

Modeling Human Prostate Cancer Metastasis in Mice via Resection of Subcutaneous Allografts.

The 5-year survival rate for patients diagnosed with distant metastatic prostate cancer in the United States is 30.6%. Therefore, there is a great need to develop in vivo model systems to study prostate cancer metastasis and to test potential therapeutics. Most murine prostate cancer metastatic models involve intracardiac or intraosseous implantation of cancer cells, which bypass the early stages of tumor cell migration and invasion. Herein we provide a detailed protocol for a novel method of resecting subcutaneous prostate cancer allografts in immunocompetent mice to produce spontaneous metastases and describe a pilot study using this method of tumor resection. Intact male FVB/NCrl mice (n = 9) were inoculated subcutaneously with Myc-CaP cells. Tumors were surgically resected, and mice were monitored for tumor recurrence. Animals were euthanized or died, and a full set of tissues was collected for histopathologic examination. Tumors took an average of 44 days (range 23-61) to reach 1.7 cm in any direction. All tumors were resectable, and resection of the tumors increased the study length by 70 days (range 30-121). One mouse was euthanized early of an unrelated cause, and of eight remaining mice, four developed tumor recurrence at the site of resection. One mouse developed bone metastases, one mouse developed metastases to the abdominal cavity, and two mice showed signs of local invasion. This study demonstrates that resection of subcutaneous Myc-CaP cell allografts in mice results in local tumor recurrence and the development of distant metastases, providing a new model system to study prostate cancer metastasis in vivo.

Association of B7-H3 expression with racial ancestry, immune cell density, and androgen receptor activation in prostate cancer.

BACKGROUND: B7 homolog 3 (B7-H3) is an immunomodulatory molecule that is highly expressed in prostate cancer (PCa) and belongs to the B7 superfamily, which includes PD-L1. Immunotherapies (antibodies, antibody-drug conjugates, and chimeric antigen receptor T cells) targeting B7-H3 are currently in clinical trials; therefore, elucidating the molecular and immune microenvironment correlates of B7-H3 expression may help to guide trial design and interpretation. The authors tested the interconnected hypotheses that B7-H3 expression is associated with genetic racial ancestry, immune cell composition, and androgen receptor signaling in PCa. METHODS: An automated, clinical-grade immunohistochemistry assay was developed by to digitally quantify B7-H3 protein expression across 2 racially diverse cohorts of primary PCa (1 with previously reported transcriptomic data) and pretreatment and posttreatment PCa tissues from a trial of intensive neoadjuvant hormonal therapy. RESULTS: B7-H3 protein expression was significantly lower in self-identified Black patients and was inversely correlated with the percentage African ancestry. This association with race was independent of the significant association of B7-H3 protein expression with ERG/ETS and PTEN status. B7-H3 messenger RNA expression, but not B7-H3 protein expression, was significantly correlated with regulatory (FOXP3-positive) T-cell density. Finally, androgen receptor activity scores were significantly correlated with B7-H3 messenger RNA expression, and neoadjuvant intensive hormonal therapy was associated with a significant decrease in B7-H3 protein expression. CONCLUSIONS: The current data underscore the importance of studying racially and molecularly diverse PCa cohorts in the immunotherapy era. This study is among the first to use genetic ancestry markers to add to the emerging evidence that PCa in men of African ancestry may have a distinct biology associated with B7-H3 expression. LAY SUMMARY: B7-H3 is an immunomodulatory molecule that is highly expressed in prostate cancer and is under investigation in clinical trials. The authors determined that B7-H3 protein expression is inversely correlated with an individual's proportion of African ancestry. The results demonstrate that B7-H3 messenger RNA expression is correlated with the density of tumor T-regulatory cells. Finally, in the first paired analysis of B7-H3 protein expression before and after neoadjuvant intensive hormone therapy, the authors determined that hormone therapy is associated with a decrease in B7-H3 protein levels, suggesting that androgen signaling may positively regulate B7-H3 expression. These results may help to guide the design of future clinical trials and to develop biomarkers of response in such trials.