Primary Prostatic Adenocarcinoma Research Articles

Incidental Uptake of 68Ga-DOTA-IBA in Prostate Adenocarcinoma.

68Ga-labeled DOTA-ibandronic acid (68Ga-DOTA-IBA) is a novel PET agent developed for bone tumors. In addition, 68Ga-DOTA-IBA uptake in nonosseous findings has also been reported. Herein, we present a case of 68Ga-DOTA-IBA uptake in primary prostate adenocarcinoma.

Pharmacokinetic Comparison of Selective Prostatic Arterial and Intravenous PSMA PET/CT Radioligand Infusions in Primary Prostatic Adenocarcinoma.

Background Intravenous prostate-specific membrane antigen (PSMA)-targeted radioligand therapy improves survival in men with metastatic castration-resistant prostate cancer. Yet, the impact of selective prostatic arterial administration on primary tumor uptake is unclear. Purpose To compare gallium 68 (68Ga)-PSMA-11 uptake using dynamic PET/CT in prostatic tumoral volumes of interest (VOIs) during intravenous and selective prostatic arterial infusions for individuals with untreated, high-risk prostate cancer. Materials and Methods In this prospective, intraindividual comparative study conducted at an academic medical center, five men aged 58, 61, 64, 66, and 68 years with treatment-naive prostate cancer were enrolled between January 2022 and February 2023 and underwent two dynamic 68Ga-PSMA-11 PET/CT examinations 1 week apart. During the first examination, the radiotracer was administered intravenously. During the second administration, the radiotracer was delivered into either the right or left prostatic artery through an angiographically placed microcatheter. The primary outcome was maximum standardized uptake value (SUVmax) in prostatic tumoral VOIs. The secondary outcomes included mean SUV (SUVmean) in prostatic tumoral VOIs and area under the SUVmean curves (AUC). Longitudinal mixed-effects models were used to compare dynamic SUVmax and SUVmean time-activity curves (TACs), and paired t tests were used for the remaining data. Results The mean SUVmax within tumoral VOIs was 14 (range, 3-43) for venous sessions and 938 (range, 460-1436) for arterial sessions (P = .008). The SUVmean within VOIs was greater during arterial sessions (P < .001) overall and 46-fold and 19-fold greater at peak uptake and final time points, respectively. The mean AUC was greater on arterial TACs than on venous TACs at 14600 SUV × min (range, 8353-20025 SUV × min) and 240 SUV × min (range, 69-622 SUV × min), respectively (P = .002). Conclusion Selective prostatic arterial infusion resulted in greater 68Ga-PSMA-11 tumoral SUV than intravenous infusion. Further study of local-regional, intra-arterial delivery of a PSMA-targeted theranostic agent is warranted in high-risk prostate cancer. ClinicalTrials.gov identifier: NCT04976257 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Civelek in this issue.

Immunohistochemical ERG positivity is associated with decreased PSMA expression and lower visibility in corresponding [68Ga]Ga-PSMA-11 PET scans of primary prostate cancer.

TMPRSS2:ERG gene fusion negatively regulates PSMA expression in prostate adenocarcinoma (PCa) cell lines. Therefore, immunohistochemical (IHC) ERG expression, a surrogate for an underlying ERG rearrangement, and PSMA expression patterns in radical prostatectomy (RPE) specimens of primary PCa, including corresponding PSMA-PET scans were investigated. Two cohorts of RPE samples (total n=148): In cohort #1 (n=62 patients) with available RPE and preoperative [68Ga]Ga-PSMA-11 PET, WHO/ISUP grade groups, IHC-ERG (positive vs. negative) and IHC-PSMA expression (% PSMA-negative tumour area, PSMA%neg) were correlated with the corresponding SUVmax. In the second cohort #2 (n=86 patients) including RPE only, same histopathological parameters were evaluated. Cohort #1: PCa with IHC-ERG expression (35.5%) showed significantly lower IHC-PSMA expression and lower SUVmax values on the corresponding PET scans. Eight of 9 PCa with negative PSMA-PET scans had IHC-ERG positivity, and confirmed TMPRSS2::ERG rearrangement. In IHC-PSMA positive PCa, IHC-ERG positivity was significantly associated with lower SUVmax values. In cohort #2, findings of higher IHC-PSMA%neg and IHC-ERG expression was confirmed with only 0-10% PSMA%neg tumour areas in IHC-ERG-negative PCa. IHC-ERG expression is significantly associated with more heterogeneous and lower IHC-PSMA tissue expression in two independent RPE cohorts. There is a strong association of ERG positivity in RPE tissue with lower [68Ga]Ga-PSMA-11 uptake on corresponding PET scans. Results may serve as a base for future biomarker development to enable tumour-tailored, individualized imaging approaches.

Evaluation of the Expression EGFR, HER2/NEU and the End Effector ERK of the RAS/RAF/MAP Kinase Pathway in Prostatic Adenocarcinoma for a Possible Role as New Target Therapy.

Immunohistochemistry- using tissue microarrays- for EGFR, HER2/neu, non-phosphorylated, and phosphor-ERK, was performed on tissues from 166 patients- with primary prostatic adenocarcinoma with no prior treatment-. The results of different markers expression were correlated with the clinical and pathological parameters and were analyzed statistically. The prostatic tissue showed EGFR, HER2 neu, phosphorylated and non-phosphorylated ERK expression in 8.4%, 1.4%, 78.2%, and 83.4% respectively whether low (patchy) or high expression (diffuse). There were no significant correlations found between patient characteristics and expression of the tested markers. The negative immune reactivity for non-phosphorylated ERK and EGFR- was significantly correlated with high tumor stage (p values 0.03 and 0.01, respectively). EGFR and HER2/neu may play a limited role in prostatic adenocarcinoma as they showed positive expression in a limited number of the examined tissues specifically HER2neu. The expression of non-phosphorylated ERK (mostly weak to moderate) and phosphorylated ERK (mostly moderate to strong)- was appreciated in most cases. Thus, we suggest that anti-EGFR drugs may have a limited role in the treatment of castrate-resistant prostate cancer, but anti-MEK/ERK drugs may have more promising role as a target therapy. It is recommended to perform further molecular testing to elucidate the exact mechanism and significance of these markers.

Abstract LB324: STING protein expression is increased in intermediate luminal cells in proliferative inflammatory atrophy of the prostate (PIA) and is absent in the majority of primary prostatic adenocarcinomas

Abstract Unresolved chronic inflammation has been postulated to drive prostate cancer development. We have proposed that proliferative inflammatory atrophy (PIA) can lead to the development of preneoplastic high grade prostatic intraepithelial neoplasia (PIN) lesions and/or directly to adenocarcinoma at times. Additionally, some PIA cells harbor molecular alterations seen in PIN and invasive carcinoma lesions, with a low frequency of PIA cells showing MYC over-expression, partial promoter hypermethylation and silencing of GSTP1, and formation of ETS gene fusions. PIA appears to result from inflammatory injury and regeneration in which proliferative and atrophic epithelial cells have an intermediate cell phenotype with both luminal and basal cell features, including basal cell markers, keratin 5 and BCL2, as well as varying levels of prostate luminal enriched genes such as androgen receptor, PSA and NKX3.1. Also, a number of gene products that are apparently stress induced, which are not expressed in normal prostate are induced in at least a subset of intermediate luminal cells in PIA, including GSTA1, PTGS2, LTF and PIGR (PMIDs:17384581, 37550827). Stimulator of interferon genes (STING), encoded by TMEM173, is a multipass transmembrane ER associated protein, and is a critical hub for innate responses directed against numerous bacterial, viral and parasitic pathogens, and is important for the induction and maintenance of adaptive immunity in a number of situations. Here, we examined STING expression by IHC, using a genetically validated assay, and show that the majority of atrophic prostatic luminal epithelial cells in all PIA lesions (N=20) consistently express high levels of STING, which is present in normal prostatic basal epithelial cells yet absent in normal-appearing prostatic luminal cells. In primary prostatic adenocarcinomas (&amp;gt; 260 tumors), STING protein was either completely negative , or extremely low in ~ 95% of cases. That STING in PIA is activate is supported by single cell RNA sequencing (scRNAseq) data from human prostatectomy tissues that show cells with the phenotype of intermediate luminal cells, indicative of PIA, express a number of interferon response genes that are not expressed in normal luminal cells (PMID 37905029). To our knowledge this is the first systematic report of STING protein staining in human prostate cancer and benign tissues. We postulate that upregulation of STING in human intermediate cells in PIA represents an inflammatory response that can drive interferon stimulated gene expression and inflammation in PIA. This innate immune response is absent, potentially by gene silencing, in prostatic adenocarcinoma, which may help neoplastic cells evade the immune response and could help contribute to the long standing finding that most prostate cancers are immunologically cold. Citation Format: Thomas M. Steele, Alan K. Meeker, Mindy K. Graham, Rulin Wang, Carolina Gomes-Alexandre, William G. Nelson, Fernanda Caramella Pereiria, Sushant Kachhap, Srinivasan Yegnasubramanian, Angelo Michael De Marzo. STING protein expression is increased in intermediate luminal cells in proliferative inflammatory atrophy of the prostate (PIA) and is absent in the majority of primary prostatic adenocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB324.

Abstract 4349: Characterization of a centrosome loss-induced tumorigenic signature in prostate epithelial cells

Abstract Prostate cancer (PCa) stands as the second leading cause of cancer death in American men, with overtreatment being common given the difficulty in distinguishing between indolent and aggressive cases. Unlike many cancers, PCa lacks hallmark mutations in key oncogenes and tumor-suppressor genes. Instead, PCa exhibit extensive genomic rearrangements and chromosomal instability (CIN). CIN occurs during PCa progression, producing ETS gene family fusions, PTEN loss and androgen receptor amplification. Importantly, the mechanism underlying CIN in PCa remains unclear. Previously, we found that cell within early-grade human primary prostate adenocarcinomas (PRAD) frequently lack centrosomes, and this frequency correlates with tumor grade. We demonstrated that transient removal of centrosomes within non-tumorigenic human prostate epithelial cells (hPrEC) induces CIN and was, strikingly, sufficient to transform subpopulations of cells capable of producing xenograft tumors in mice. To unravel the molecular mechanisms underlying this path to tumorigenesis, we isolated DNA and RNA from parental hPrECs, clonal lines subjected to transient centrosome loss, and xenograft tumor cells and performed whole genome sequencing (WGS) and bulk RNA-seq. This allowed us to characterize the genomic profiles induced by centrosome loss and to identify an associated mutational signature. We used MUTECT2 to identify single nucleotide variants. Kataegis loci were observed on multiple chromosomes in all transient centrosome removal samples. Copy number variations were also detected in these samples using FACETS and SEQUENZA. Next, we extracted the copy number (CN) signature with SigProfiler and Sigminer, comparing it to COSMIC CN signatures and WGS data from PRAD patients. Our results revealed that the transient centrosome loss signature bears similarity to CN signatures associated with chromothripsis, loss of heterozygosity, and homologous recombination repair deficiency. Patients with PRAD displaying the centrosome loss CN signature had a poorer prognosis. Additionally, our CN analysis discovered that centrosome loss induced mosaic loss of chromosome Y in our samples. To detect structural variations, we employed DELLY, MANTA, SVABA, revealing a high occurrence of both non-clustered and clustered translocations in transient centrosome loss samples. These translocations were validated in our RNA-seq data using STAR-Fusion. Ongoing analyses include inferring CNV from PCa scRNA-seq data, and determining cell populations with the centrosome loss CN-signature and their associated transcriptome features. This work unveils a comprehensive genomic profile stemming from centrosome loss and demonstrates its role in driving oncogenesis in PCa. These findings have the potential to establish centrosome loss as a hallmark in PCa stratification, and lead to a significant advancement in prostate tumor treatment. Citation Format: Jiawen Yang, Diogo de Oliveira Pessoa, John M. Ryniawec, Emily Loertscher, Anne E. Cress, Megha Padi, Gregory C. Rogers. Characterization of a centrosome loss-induced tumorigenic signature in prostate epithelial cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4349.

Abstract 861: Integrative multi-omics analysis enables a comprehensive characterization of prostate cancer and unveils metastasis-associated candidate biomarkers

Abstract Prostate cancer (PCa), a common malignancy in men, presents a complex and variable disease landscape, requiring precise evaluation for personalized treatment decisions. Urologists employ a range of assessments, including clinical staging, PSA levels, imaging, Gleason scores, and emerging biomarkers. Nevertheless, the need for additional biomarkers to enhance precision medicine continues. This study utilizes extensive omics datasets to thoroughly profile PCa. We conducted an in-depth analysis of primary PCa data from the multi-omics dataset from The Cancer Genome Atlas studies to identify molecular subtypes showing significant prognostic differences. We conducted integrative clustering analysis on a dataset comprising 341 primary prostate adenocarcinomas with comprehensive multi-omics data, including substitutions, small insertions/deletions, copy number alterations, DNA methylation, gene expression profiles, micro-RNA expression, reverse-phase protein arrays, and microbiome data. The analysis revealed seven distinct clusters (C1 to C7) based on multi-omics features. At the genomic level, recurrent copy number losses and DNA methylation/demethylation were the most prominent alterations across clusters. When looking at survival curves, the 7 clusters could be clearly partitioned into two groups. Therefore, to further investigate multi-omics features specifically linked to prognosis, we grouped clusters with similar prognoses into two macro-clusters. Clusters C1 to C4 formed MC1 (favorable prognosis), while C5 to C7 constituted MC2 (poor prognosis). A comprehensive comparison between MC1 and MC2 revealed molecular differences associated with survival. We performed computational validation of candidate prognostic biomarkers using two external datasets. By utilizing these selected features, we could stratify patients in both the validation datasets into groups with significant differences in survival. The analysis identified six features consistently associated with prognosis across both datasets, including CCNB1, PCNA, RAD51, FOXM1, miR-503-5p (positively associated with risk), and miR-7704 (negatively associated with risk). The practical applicability of these biomarkers was explored through immunohistochemical analysis on biopsy samples obtained at diagnosis and from metastatic sites. Based on their potential relevance according to the literature, we investigated three candidate biomarkers derived from the multi-omics analysis: FOXM1, CCNB1 and RAD51. The expression of these proteins was found to correlate with PCa progression and mark the metastatic stage. In summary, this study highlights the potential of translating comprehensive multi-omics bioinformatic analyses into practical approaches for understanding the molecular mechanisms of tumors and identifying prognostic markers. Citation Format: Matteo Villa, Giorgio Cazzaniga, Maddalena Bolognesi, Valentina Crippa, Federica Malighetti, Andrea Aroldi, Giorgio Bozzini, Fabio Pagni, Rocco Piazza, Luca Mologni, Daniele Ramazzotti. Integrative multi-omics analysis enables a comprehensive characterization of prostate cancer and unveils metastasis-associated candidate biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 861.

Genomic attributes of prostate cancer across primary and metastatic noncastrate and castrate resistant disease states: a next generation sequencing study of 183 patients.

Primary prostatic adenocarcinoma (pPC) undergoes genomic evolution secondary to therapy-related selection pressures as it transitions to metastatic noncastrate (mNC-PC) and castrate resistant (mCR-PC) disease. Next generation sequencing results were evaluated for pPC (n = 97), locally advanced disease (involving urinary bladder/rectum, n = 12), mNC-PC (n = 21), and mCR-PC (n = 54). We identified enrichment of TP53 alterations in high-grade pPC, TP53/RB1 alterations in HGNE disease, and AR alterations in metastatic and castrate resistant disease. Actionable alterations (MSI-H phenotype and HRR genes) were identified in approximately a fifth of all cases. These results help elucidate the landscape of genomic alterations across the clinical spectrum of prostate cancer.

Clinicopathologic Characterization of Prostatic Cancer in Dogs.

Clinicopathologic data in dogs with prostate cancer (PCa) may aid in the differentiation between tumor types and subsequent treatment decisions; however, these data are often unreported. Demographic, clinicopathologic, cytologic, histologic and survival data from dogs with primary prostatic adenocarcinoma (PRAD) (n = 56) and primary prostatic transitional cell carcinoma (P-TCC) (n = 74) were acquired from a tertiary veterinary teaching hospital from 1992 to 2022. Red blood cell distribution width (RDW) to albumin ratio (RAR) was evaluated for diagnostic utility in differentiating between PRAD and P-TCC. Sections from PRAD tumors (n = 50) were stained for androgen receptor (AR) expression, and laboratory data were compared between AR positive (AR+) and AR negative (AR-) groups. RDW was increased in PRAD, while albumin was decreased (p < 0.05). P-TCC was associated with Melamed-Wolinska bodies (MWB) and necrosis on cytology (p < 0.05). RAR had acceptable diagnostic utility in the differentiation of PCa tumors (AUC = 0.7; p < 0.05). Survival rates and metastases were equivocal. AR+ and AR- PRAD tumors did not differ in clinicopathologic data or survival (p > 0.05). In conclusion, hypoalbuminemia was significantly associated with PRAD and decreased survival, while MWB and necrosis were significantly associated with P-TCC on cytology. These clinicopathologic data may help clinicians differentiate between these tumors ante mortem to guide appropriate treatment and intervention.

Predicting prostate cancer progression with a Multi-lncRNA expression-based risk score and nomogram integrating ISUP grading

Prostate cancer is a highly heterogeneous disease; therefore, estimating patient prognosis accurately is challenging due to the lack of biomarkers with sufficient specificity and sensitivity. One of the current challenges lies in integrating genomic and transcriptomic data with clinico-pathological features and in incorporating their application in everyday clinical practice. Therefore, we aimed to model a risk score and nomogram containing long non-coding RNA (lncRNA) expression and clinico-pathological data to better predict the probability of prostate cancer progression. We performed bioinformatics analyses to identify lncRNAs differentially expressed across various prostate cancer stages and associated with progression-free survival. This information was further integrated into a prognostic risk score and nomogram containing transcriptomic and clinico-pathological features to estimate the risk of disease progression. We used RNA-seq data from 5 datasets from public repositories (total n = 178) comprising different stages of prostate cancer: pre-treatment primary prostate adenocarcinomas, post-treatment tumors and metastatic castration resistant prostate cancer. We found 30 lncRNAs with consistent differential expression in all comparisons made using two R-based packages. Multivariate progression-free survival analysis including the ISUP group as covariate, revealed that 7/30 lncRNAs were significantly associated with time-to-progression. Next, we combined the expression of these 7 lncRNAs into a multi-lncRNA score and dichotomized the patients into low- or high-score. Patients with a high-score showed a 4-fold risk of disease progression (HR = 4.30, 95 %CI = 2.66–6.97, p = 3.1e-9). Furthermore, we modelled a combined risk-score containing information on the multi-lncRNA score and ISUP group. We found that patients with a high-risk score had nearly 8-fold risk of progression (HR = 7.65, 95 %CI = 4.05–14.44, p = 3.4e-10). Finally, we created and validated a nomogram to help uro-oncologists to better predict patient's risk of progression at 3- and 5-years post-diagnosis. In conclusion, the integration of lncRNA expression data and clinico-pathological features of prostate tumors into predictive models might aid in tailored disease risk assessment and treatment for patients with prostate cancer.

TRPS1 expression in primary and metastatic prostatic adenocarcinoma, muscle invasive bladder urothelial carcinoma, and breast carcinoma: Is TRPS1 truly specific and sensitive for a breast primary?

Trichorhinophalangeal syndrome type 1 (TRPS1) has been reported to be a sensitive and specific immunohistochemical (IHC) marker for breast carcinomas, especially when determining primary site of origin. However, there is limited data on TRPS1 expression in prostate and bladder cancers.A two-phase study was performed with 1) an exploratory cohort analyzing TRPS1 gene alterations in prostate, bladder, and breast carcinoma and TPRS1 mRNA expression data in prostate and bladder carcinoma; and 2) TRPS1 and GATA3 IHC in a confirmatory cohort in prostate, bladder, and breast carcinoma samples.Gene alterations were identified in a subset of breast, bladder, and prostate carcinomas and mRNA was consistently detected. In the IHC cohort, 183/210 (87.1 %) of breast, 22/69 (31.9 %) of prostate, and 20/73 (27.4 %) of urothelial carcinomas showed staining with TRPS1. Intermediate to high expression of TRPS1 was observed in 173/210 (82.8 %) of breast, 17/69 (24.6 %) of prostate, and 15/73 (20.5 %) of urothelial carcinomas. Furthermore, in prostate cancer, 26.9 % of pelvic lymph node metastases and 50 % in sites of distant metastases showed expression. Increased TRPS1 mRNA expression (p = 0.032) and IHC expression (p = 0.040) correlated with worse overall survival in bladder cancer. By comparison, GATA3 IHC stained 136/210 (64.8 %) of breast, 0/69 (0 %) of prostate, and 63/73 (93 %) of bladder carcinomas. Intermediate to high expression of GATA3 was seen in 131/210 (62.4 %) of breast and 63/73 (93 %) of bladder carcinomas.This study shows there is significant staining of TRPS1 in bladder and prostate cancers. As a result, comprehensive studies are needed to establish the true specificity of TRPS1 IHC stain across various tumor types before its widespread clinical adoption.

Determinants of Widespread Metastases and of Metastatic Tropism in Patients with Prostate Cancer: A Genomic Analysis of Primary and Metastatic Tumors

A growing body of evidence suggests that metastatic cancer is better described as a spectrum of disease rather than a binarily defined state, ranging from oligometastatic cancer to widespread metastases. Widespread metastases represent the most common cause of cancer-related death among patients with prostate cancer. Therefore, a greater understanding of the genomic features that determine the extent and location of metastatic spread may inform risk stratification, treatment, and monitoring. We identify genomic alterations from primary prostate tumors that are predictive of widespread metastatic potential. Genomic and clinical data for 1,312 patients with primary prostate adenocarcinomas were extracted from the MSK-MET cohort through cBioPortal. Metastatic site counts and overall survival (OS) data were publicly available for all patients. All samples from primary tumors were profiled using the MSK-IMPACT targeted sequencing platform. Our study focused on 58 genes frequently altered in prostate cancer. Cox proportional hazard analyses defined hazard ratios (HRs) and 95% confidence intervals (CIs) for overall mortality in patients with different metastatic outcomes. Patterns of genomic alterations of the primary tumor associated with metastatic extent and location were compared. Out of 1,312 patients, 939 (71%) developed metastases, and 113 (8.6%) had metastases to 5 or more distinct anatomical sites (defining wide-spread metastases, WSM). Bone was the most common site of metastasis (36%), and 80% of patients with liver metastases had 4 or more additional sites of metastasis. Among patients with metastases, increasing number of metastatic sites was associated with increased risk of death (HR:1.8, 95% CI:1.63-1.99, p<0.001). To define genomic determinants of WSM, we characterized genomic alterations in 58 prostate cancer related genes. Alterations in the following genes were enriched in tumors from patients with WSM vs others: TP53 mutation (40% vs 20%, p<0.0001), FOXA1-amplification (8% vs 3%, p = 0.02), AR-amplification (4.4% vs 1%, p = 0.01), RB1-deletion (5.3% vs 0.7%, p = 0.001), and BRCA2-deletion (4.4% vs 0.7%, p = 0.01). In a univariable survival analysis, all these alterations were predictive of OS (p<0.05). However, on multivariable analysis, only TP53 mutations, and FOXA1 and AR amplifications were independent prognostic factors. Amplifications of FOXA1 (n = 37) and AR (n = 13) were mutually exclusive (0 overlap), and we found that patients who have either AR or FOXA1 amplifications experienced very poor OS (HR:3.57, 95% CI:2.26-5.6, p p<0.001]. We identified genomic alterations (TP53 mutations, FOXA1 and AR amplification, RB1 and BRCA2 deletions) from primary prostate tumors that are predictive of wide-spread metastases and poor outcomes.

Determinants of widespread metastases and of metastatic tropism in patients with prostate cancer: A genomic analysis of primary and metastatic tumors.

5067 Background: A growing body of evidence suggests that metastatic cancer is better described as a spectrum of disease rather than a binarily defined state, ranging from oligometastatic cancer to widespread metastases. Widespread metastases represent the most common cause of cancer-related death among patients with prostate cancer. Therefore, a greater understanding of the genomic features that determine the extent and location of metastatic spread may inform risk stratification, treatment, and monitoring. We identify genomic alterations from primary prostate tumors that are predictive of widespread metastatic potential. Methods: Genomic and clinical data for 1,312 patients with primary prostate adenocarcinomas were extracted from the MSK-MET cohort through cBioPortal. Metastatic site counts and overall survival (OS) data were publicly available for all patients. All samples from primary tumors were profiled using the MSK-IMPACT targeted sequencing platform. Our study focused on 58 genes frequently altered in prostate cancer. Cox proportional hazard analyses defined hazard ratios (HRs) and 95% confidence intervals (CIs) for overall mortality in patients with different metastatic outcomes. Patterns of genomic alterations of the primary tumor associated with metastatic extent and location were compared. Results: Out of 1,312 patients, 939 (71%) developed metastases, and 113 (8.6%) had metastases to 5 or more distinct anatomical sites (defining wide-spread metastases, WSM). Bone was the most common site of metastasis (36%), and 80% of patients with liver metastases had 4 or more additional sites of metastasis. Among patients with metastases, increasing number of metastatic sites was associated with increased risk of death (HR:1.8, 95%CI:1.63-1.99, p&lt;0.001). To define genomic determinants of WSM, we characterized genomic alterations in 58 prostate cancer related genes. Alterations in the following genes were enriched in tumors from patients with WSM vs others: TP53 mutation (40% vs 20%, p&lt;0.0001), FOXA1-amplification (8% vs 3%, p=0.02), AR-amplification (4.4% vs 1%, p=0.01), RB1-deletion (5.3% vs 0.7%, p=0.001), and BRCA2-deletion (4.4% vs 0.7%, p=0.01). In a univariable survival analysis, all these alterations were predictive of OS (p&lt;0.05). However, on multivariable analysis, only TP53 mutations, and FOXA1 and AR amplifications were independent prognostic factors. Amplifications of FOXA1 (n=37) and AR (n=13) were mutually exclusive (0 overlap), and we found that patients who have either AR or FOXA1 amplifications experienced very poor OS (HR:3.57, 95%CI:2.26-5.6, p p&lt;0.001]. Conclusions: We identified genomic alterations (TP53 mutations, FOXA1 and AR amplification, RB1 and BRCA2 deletions) from primary prostate tumors that are predictive of wide-spread metastases and poor outcomes.

Immunogenomic Landscape of Neuroendocrine Prostate Cancer.

Patients with neuroendocrine prostate cancer (NEPC) are often managed with immunotherapy regimens extrapolated from small-cell lung cancer (SCLC). We sought to evaluate the tumor immune landscape of NEPC compared with other prostate cancer types and SCLC. In this retrospective study, a cohort of 170 patients with 230 RNA-sequencing and 104 matched whole-exome sequencing data were analyzed. Differences in immune and stromal constituents, frequency of genomic alterations, and associations with outcomes were evaluated. In our cohort, 36% of the prostate tumors were identified as CD8+ T-cell inflamed, whereas the remaining 64% were T-cell depleted. T-cell-inflamed tumors were enriched in anti-inflammatory M2 macrophages and exhausted T cells and associated with shorter overall survival relative to T-cell-depleted tumors (HR, 2.62; P < 0.05). Among all prostate cancer types in the cohort, NEPC was identified to be the most immune depleted, wherein only 9 out of the 36 total NEPC tumors were classified as T-cell inflamed. These inflamed NEPC cases were enriched in IFN gamma signaling and PD-1 signaling compared with other NEPC tumors. Comparison of NEPC with SCLC revealed that NEPC had poor immune content and less mutations compared with SCLC, but expression of checkpoint genes PD-L1 and CTLA-4 was comparable between NEPC and SCLC. NEPC is characterized by a relatively immune-depleted tumor immune microenvironment compared with other primary and metastatic prostate adenocarcinoma except in a minority of cases. These findings may inform development of immunotherapy strategies for patients with advanced prostate cancer.

Immunohistochemical Expression of NKX3.1 in Prostatic Adenocarcinoma Correlates with Tumors Grade among Sudanese

Background: The second most frequent cancer in males and the fourth most common cancer overall for both sexes is prostate cancer. On chromosome 8p, there is a prostatic tumor suppressor gene called NKX3.1. Despite the fact that the majority of primary prostatic adenocarcinomas exhibit positive NKX3.1 protein staining. Objective: The purpose of this study was to evaluate the immunohistochemical expression of NKX3.1in prostate adenocarcinoma and correlate it with tumor grades among Sudanese patients. Materials and Methods: This study is a retrospective descriptive cross- sectional study, was conducted in Khartoum state, (Radiation&amp; Istopes Center- Khartoum (RICK)). Tissue sections were stained by immunohistochemical staining against NKX3.1 (indirect dextral polymers (Dako- EnVision TM Flex kit)) was carried out on forty (40) archival formalin fixed paraffin embedded tissue blocks from patients diagnosed as prostate carcinoma. Data were collected from hospital records and the immunohistochemical results and then analyzed using SPSS 25.0 frequency, and Chi-Square and mean were calculated. Results: The study found that the most frequent age group is between (71 – 80) years old, twenty (20) cases have prostate adenocarcinoma grade III, twelve (12) cases were grade II, and eight (8) cases were grade I. Any nuclear NKX3.1 staining was regarded as positive. Thirty-five (35%) have NKX3 positive immunostain while (65%) have a negative result. There is a statistically significant correlation between the NKX3.1 expressions and tumor grade as the P. value was (0.000), while in a statistically significant correlation between the NKX3 expressions and patients' age as the P. value was (0.957). Conclusions: NKX3 immuno expression is strongly associated with higher tumor grade and may prove the role of this protein in the progression of prostate cancer.

Metagenomic insights into the plasma virome of Brazilian patients with prostate cancer

ABSTRACT Growing evidence suggests that metavirome changes could be associated increased risk for malignant cell transformation. Considering Viruses have been proposed as factors for prostate cancer induction. The objective of this study was to examine the composition of the plasma metavirome of patients with prostate cancer. Blood samples were obtained from 49 male patients with primary prostate adenocarcinoma. Thirty blood donors were included as a control group. The obtained next-generation sequencing data were analyzed using a bioinformatic pipeline for virus metagenomics. Viral reads with higher abundance were assembled in contigs and analyzed taxonomically. Viral agents of interest were also confirmed by qPCR. Anelloviruses and the Human Pegivirus-1 (HPgV-1) were the most abundant component of plasma metavirome. Clinically important viruses like hepatitis C virus (HCV), cytomegalovirus and human adenovirus type C were also identified. In comparison, the blood donor virome was exclusively composed of torque teno virus types (TTV) types. The performed HPgV-1 and HCV phylogeny revealed that these viruses belong to commonly detected in Brazil genotypes. Our study sheds light on the plasma viral abundance in patients with prostatic cancer. The obtained viral diversity allowed us to separate the patients and controls, probably suggesting that malignant processes may influence virome composition. More complex and multiple approach investigations are necessary to examine the likely causal relationship between metavirome and its nvolvement in prostate cancer.

Confirmation of PSMA expression measured on [68Ga]Ga-PSMA PET/CT by immunohistochemistry in prostate adenocarcinoma.

Our aim is to determine the accuracy of [68Ga]Ga-PSMA PET/CT in showing PSMA expression in primary prostate cancer and to investigate the relationship between SUVmax and immunohistochemical PSMA expression, Gleason score, and PSA value. We retrospectively analyzed 66 male patients who were diagnosed with primary prostate adenocarcinoma, underwent pre-treatment [68Ga]Ga-PSMA PET/CT examination for staging, and performed radical prostatectomy between March 2018-August 2020. Immunohistochemical staining was applied to the radical prostatectomy specimens of all patients to detect PSMA expression. The results were evaluated as an immunoreactive score (IRS) and a modified IRS was obtained. Gleason score groups and prostate-specific antigen (PSA) serum values of the patients were obtained from the patient files. The high SUVmax of primary prostate tumors was significantly correlated with a high modified IRS score (score 2; 3), high PSA value, high Gleason score, and metastasis. In correlation analysis, a positive correlation was found between SUVmax and PSA value and modified IRS score (r = 0.69, p = 0.001; r = 0.39, p = 0.001). In addition, there was a statistically significant weak correlation between PSA serum concentration and modified IRS scores (r = 0.267; p = 0.03). In regression analysis, the percentage of positive cells had a statistically significant and increasing effect on SUVmax (p = 0.031; std beta = 0.268; 95% CI = 0.231-4.596). In prostate adenocarcinoma, SUVmax of the primary tumor in [68Ga]Ga-PSMA PET/CT correlates with immunohistochemical PSMA expression. In addition, high SUVmax is associated with markers of poor prognoses, such as high PSMA expression, PSA value, and Gleason score.

Alpha thalassemia/intellectual disability syndrome X-linked expression varies significantly between androgen receptor-positive and androgen receptor-negative prostatic adenocarcinoma: Relation to epidermal growth factor receptor expression and clinicopathological factors

Background: Prostate cancer (PC) is the most common cancer and a leading cause of cancer-related mortality in men worldwide. It has become clear that signaling pathways that are implicated in prostatic carcinoma (PCa) initiation and propagation evolved through interactions of several factors. Alpha Thalassemia/Intellectual Disability syndrome X-linked (ATRX) is a chromatin remodeling protein that has an essential role in telomere stability. The androgen receptor (AR) and growth factors especially the epidermal growth factor receptor (EGFR) seem not to function independently in PCa proliferation. This work aimed to study the expression of ATRX in primary prostatic adenocarcinoma in relation to AR and EGFR expression and the significance of biomarkers expression to the known clinicopathological factors. Materials and Methods: Eighty-two primary prostatic adenocarcinoma paraffin blocks were stained immunohistochemically with AR, ATRX, and EGFR polyclonal antibodies. PCa was divided into AR+/hi and AR−/lo depending on the percentage and intensity of stained cells regardless of AR heterogeneity. ATRX immunostaining was categorized into ATRX preserved expression or ATRX loss. EGFR expression was grouped into low and high expression according to the staining percentage and intensity. Results: AR+/hi and preserved ATRX expression significantly were linked to low pT stage, low-grade group, and absence of lymph node invasion. While significant EGFR high expression was related to the high-grade group and the presence of lymph node invasion. Conclusion: ATRX preserved expression varies significantly between AR+/hi and AR−/lo PCa which is related to favorable clinicopathological factors. However, the loss of ATRX expression correlated significantly with AR−/low, high EGFR expression, and adverse clinicopathological factors.

Cutaneous Scrotal Metastasis Secondary to Primary Prostate Adenocarcinoma Responding to Immunotherapy

This case demonstrates the aggressive progression of prostate adenocarcinoma, failing 3 treatment regimens. Although the patient initially responded to treatments, he developed cutaneous metastasis. Genomic tumor analysis of scrotal tissue confirmed targetable molecular mutations. Treatment with systemic immunotherapy was initiated with complete resolution of disease. This case reveals the rare metastasis of prostate adenocarcinoma to the scrotum with advanced refractory cancer and the successful response to immunotherapy. It illustrates the importance of tumor genomic testing in advanced refractory prostate cancer.

Abstract 1728: Single cell RNA-seq analysis reveals a role of pro-inflammatory tumor-associated macrophages in driving prostate cancer progression

Abstract Genomic amplification and increased expression of C-MYC are found in high-grade intraepithelial neoplasm (HGPIN) and primary prostate adenocarcinoma. What role C-MYC plays in the initiation and progression of prostate cancer remains unclear. A genetically engineered mouse model with a high level of human C-MYC protein expression under a probasin promoter (Hi-Myc model) was developed that captures prostate cancer progression from hyperplasia at 6-week-old, to HGPIN at 3-6 month-old, and ultimately to invasive adenocarcinoma at 8-month-old. Applying single-cell RNA sequencing (scRNA-seq) technology, we have carefully studied the temporal transcriptional change in MYC-expressing tumor-initiating cells and the tumor-infiltrating immune cells to understand the cell-intrinsic and -extrinsic mechanisms by which C-MYC promotes the transition from HGPIN to invasive prostate cancer. We have identified a particular type of luminal cells, Prom1+ L1 cells, as the likely tumor initiating cells in the Hi-Myc model. The MYC-expressing L1 tumor initiating cells were more abundant and cycling more often in the invasive cancer at 8-month-old, compared to the pre-invasive stage. Interestingly, significant infiltration of novel M1-like tumor-associated macrophages (TAMs) correlated with the histologic tumor progression from HGPIN to invasive cancer. Targeting TAMs with anti-CSF1R antibody delayed prostate cancer progression and invasion, which appears to be independent of CD8 T-cells. Mechanistically, TAMs expressed a high level of IL-1b, which stimulated Hi-Myc prostate cell proliferation in an organoid co-culture system. More importantly, depleting IL-1b with a neutralizing antibody slowed prostate cancer progression in Hi-Myc mice. Lastly, we found that increased macrophage gene expression was associated with higher Gleason scores and worse disease-free survival in a TCGA clinical patient cohort. In summary, we have identified a molecular mechanism involving pro-inflammatory TAMs and IL-1b in driving early prostate cancer progression in a MYC-driven prostate cancer model, opening a potential therapeutic avenue to target TAMs and pro-inflammatory cytokine in preventing early prostate cancer progression. Citation Format: Jimmy L. Zhao, Joseph Chan, Max Land, Perianne Smith, Anuradha Gopalan, Michael Haffner, Dana Pe'er, Charles Sawyers. Single cell RNA-seq analysis reveals a role of pro-inflammatory tumor-associated macrophages in driving prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1728.