Proliferative Inflammatory Atrophy Research Articles

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 (> 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 5323: Inflammation drives lineage plasticity and a club cell-like phenotype in prostate epithelial cells

Abstract Background: Club cells are a type of bronchiolar epithelial cell that serve a protective and antimicrobial function in the lung. An epithelial cell population in adult human prostates was recently identified as sharing a similar transcriptomic profile and morphology to lung club cells. Club-like epithelial cells were identified in the prostatic urethra, collecting ducts, and rarely in the peripheral zone of normal organ donor prostates. However, we recently reported that cells expressing club cell markers (CP, LTF, MMP7, PIGR, SCGB1A1) are present in the peripheral zone of radical prostatectomy specimens. Here, expression of club cell markers was restricted to luminal epithelial cells in an inflammation-associated lesion termed proliferative inflammatory atrophy (PIA). We also demonstrated that these club-like cells within PIA express the same markers as intermediate cells, a proposed prostate cancer progenitor cell. We now aim to identify exogenous factors that drive the club cell phenotype in vitro. Our ultimate goal is to understand how club cell gene expression affects the oncogenic and metastatic potential of prostate epithelial cells. Methods: We characterized the expression of club cell genes in prostate cell lines (LNCaP, PREC, and PREC-AR-Myc) following exposure to inflammatory stimuli (TNFα, hydrogen peroxide, uropathogenic Escherichia coli) in vitro. We performed quantitative reverse transcription PCR (RT-qPCR) to measure expression of club cell markers (LTF, MMP7, PIGR) and intermediate cell markers (AR, NKX3.1, SMOX). Additionally, we used chromogenic RNA in situ hybridization (RISH) to visualize LTF, MMP7, and PIGR expression following exposure to inflammatory stimuli. Results: We report that TNFα exposure in vitro increased expression of club cell genes (LTF, MMP7, PIGR). Surprisingly, TNFα exposure induced LTF expression in LNCaP cells, despite prior findings that LTF is silenced by CpG island hypermethylation in prostate cancer and in LNCaP cells. This finding was confirmed by both RT-qPCR and RISH. Additionally, we found that TNFα exposure altered intermediate cell markers (AR, NKX3.1, SMOX) expression consistent with the previously reported gene expression pattern of luminal epithelial cells in PIA. Conclusions: Overall, our results suggest that TNFα-mediated signaling drives the expression of club cell markers associated with lineage plasticity. Our next step will be to analyze inflammation-driven alterations to methylation and chromatin accessibility around loci associated with club cell genes, proton-oncogenes, and tumor suppressor genes. Citation Format: Megan Hess, Hanbing Song, Jessica Hicks, Luke Mummert, Angelo De Marzo, Franklin W. Huang, Karen Sfanos. Inflammation drives lineage plasticity and a club cell-like phenotype 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 5323.

Abstract 1246: Erg-driven prostate cancer emerges from a basal subset of cells with luminal transcriptomic features

Abstract Translocations of the ETS family transcription factor ERG are found in nearly 150,000 newly diagnosed prostate cancers (PCas) each year in the United States underscoring the importance of defining the mechanism by which ERG promotes prostate epithelial transformation. A consequence of nearly all ERG translocations is the aberrant expression of ERG in prostate luminal cells under transcriptional control of TMPRSS2. Multiple lines of evidence implicate ERG translocations as an initiating event in prostate cancer. ERG expression is seen in prostatic intraepithelial neoplasia (PIN) and proliferative inflammatory atrophy; expression in cancers is typically uniform; and, in the context of PI3K pathway activation, ERG is sufficient to induce cancers in mice. Yet, despite extensive research the mechanism by which ERG initiates prostate cancer is unclear. To gain insight into how ERG translocations cause prostate cancer, we performed both transcriptional profiling (scRNA-seq) and chromatin accessibility via Assay for Transposase-Accessible Chromatin using sequencing (snATAC-seq) in single cells of an autochthonous mouse model at an early stage of disease initiation. Surprisingly, we observed in prostate epithelial cells broadly expressing ERG enhanced proliferation primarily in a hybrid subpopulation of cells having basal identity but with luminal morphology and cytokeratin expression. Through a series of lineage tracing and primary prostate epithelial transplantation experiments, we confirmed tumor initiating activity resided within a subpopulation of basal cells expressing luminal genes (e.g., Tmprss2 and Nkx3-1). A trajectory analysis from single-cell Chromatin accessibility indicated Erg+ cells began to lose basal (Trp63) accessibility and gained in STAT/NFAT TFs while retaining the ability to rapidly differentiate into luminal cells that reflect the lineage of ERG-positive cancers. These findings help resolve a preexisting debate about the cell of origin of ERG-driven prostate cancer and narrow the focus for future mechanistic studies to a basal-luminal subpopulation of tumor initiating cells. Citation Format: Erik Ladewig, Weiran Feng, Christina Leslie, Charles Sawyers. Erg-driven prostate cancer emerges from a basal subset of cells with luminal transcriptomic features [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 1246.

Prostatic proliferative inflammatory atrophy: welcome to the club†.

Single-cell RNA sequencing studies in the human prostate have defined a population of epithelial cells with transcriptional similarities to club cells in the lung. However, the localization of club-like cells in the human prostate, and their relationship to prostate cancer, is poorly understood. In a new article in The Journal of Pathology, RNA in situ hybridization was used to demonstrate that club cell markers are expressed in luminal cells adjacent to inflammation in the peripheral zone of the human prostate, where prostate cancer tends to arise. These club-like cells are commonly found in proliferative inflammatory atrophy (PIA) lesions and express markers consistent with an intermediate epithelial cell-type. Future studies will be needed to understand the functional role of club-like cells in human prostate inflammation, regeneration, and disease. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

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.

Abstract 4631: Multiplex IHC assay to explore regional heterogeneity of FAP and inflammatory cell density in localized prostatic adenocarcinoma

Abstract Cancer-associated fibroblasts (CAFs) expressing FAP promote tumor growth, invasion and immune suppression. FAP is a molecular imaging target in cancer and its protease activity is a potential anti-cancer drug target. While FAP expression was associated with biochemical recurrence after prostatectomy using tissue microarrays (TMAs)(DOI:10.1158/2767-9764.CRC-21-0183), its expression has not been comprehensively correlated with morphological features of disease aggressiveness beyond grade. 48 cases of localized prostatic adenocarcinoma were used for a multiplex immunohistochemical assay that included FAP, CD45, CD163, p63 and Keratin 8. Each of these markers were individually optimized by single-plex staining and were then performed as an iterative IHC assay (PMID:35188986) and quantification was performed using the HALO image analysis platform (Indica Labs). We developed a second multiplex assay including FAP, vimentin, smooth muscle actin, desmin, CD31, S100, keratin 8 and p63. FAP IHC staining was analytically validated using a series of positive and negative cell lines. In normal appearing (non-inflamed) prostate regions, FAP expression was negative. By contrast, upregulation of FAP was observed in the stromal compartment in regions of chronic inflammation and some proliferative inflammatory atrophy (PIA) lesions. In tumor regions, only 1 case was totally negative for FAP. Except for 2 cases, in which there was focal weak tumor cell staining, all FAP expression was present in the tumor stromal compartment (TSC). The vast majority of FAP expression was associated with Vim+/Des- fibroblasts, which at times were also positive for SMA (Vim+/Des-/SMA+), indicating they are myofibroblasts. There was very infrequent FAP expression associated with M2 macrophages, endothelial cells, nerves and vimentin-negative smooth muscle cells, indicating that the majority of FAP expression occurs in fibroblasts. Preliminary quantitative data using visual estimations of the fraction of TSC expressing FAP (range, 0-80%, mean=35.8%, median=30%, SD=23.7) was not associated with the overall GS/grade group, but was associated with non-organ confined disease. Furthermore, there was a trend towards increased FAP expression in cases showing intraductal carcinoma and large cribriform formation. Ongoing studies are in process to obtain quantitative data by image analysis and to correlate FAP expression with the presence of overall inflammatory cell density and the density of M2 macrophages. Additionally, we will characterize the cases in terms of molecular features including TMPRSS2-ERG status and PTEN genomic status. Future use of these panels will facilitate studies of associations of FAP with clinical outcome, MRI and PET imaging, response to specific treatments and to help characterize FAP as a predictor of response to emerging FAP inhibitors and FAP-targeted prodrugs. Citation Format: Fernanda Caramella Pereira, Alan K. Meeker, Kenneth Pienta, Qizhi Zheng, Tracy Jones, Srinivasan Yegnasubramanian, Jessica L. Hicks, Sujayita Roy, Angelo M. De Marzo, W. Nathaniel Brennen. Multiplex IHC assay to explore regional heterogeneity of FAP and inflammatory cell density in localized prostatic adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4631.

Abstract 3734: Progressive spreading of CpG methylation in the CpG island of Glutathione S-Transferase pi 1 (GSTP1) alleles across transitions from precursor to invasive prostate cancer

Abstract Glutathione S-transferase pi 1 (GSTP1) is expressed at low levels in normal prostate luminal cells and becomes induced in most proliferative inflammatory atrophy lesions (PIA). GSTP1 becomes silenced in prostatic intraepithelial neoplasia (PIN) and prostate adenocarcinoma (CaP) via CpG island promoter hypermethylation. However, the specific methylation patterns in CaP and its precursors have not been investigated. We used bisulfite genomic sequencing to examine methylation of 39 CpG sites in the GSTP1 promoter. Radical prostatectomy specimens were selected from 32 subjects that underwent treatment for CaP. Serial sections were subjected to laser capture microdissection for enrichment of epithelial cells from benign, PIA, PIN, and CaP regions. Isolated DNA was bisulfite converted. Sequences corresponding to the GSTP1 promoter CpG island were amplified with nested PCR, and PCR products were cloned. 10 independent clones were sequenced and analyzed with a Java program, DNAMethylMap, to determine the methylation pattern of 39 CpG sites of the GSTP1 promoter in each lesion. The extent of methylation on an individual allele was classified as negative (<10% CpGs), mild (10-25%), moderate (25-50%), or high (>50%). 212 clones from 24 normal epithelium regions, 327 clones from 37 PIA regions, 167 clones from 18 PIN regions, and 202 clones from 23 CaP regions were sequenced, totaling 34863 CpG sites. Normal and PIA lesions were mostly unmethylated with 0.52% and 1.3% of total CpG sites methylated, respectively. Methylated PIA lesions were adjacent to CaP or PIN regions significantly more often than unmethylated PIA lesions (χ2, p = 0.012). PIN and CaP lesions had greater methylation with 24% and 51% of total CpG sites methylated, respectively. PIN lesions generally showed partial methylation with 28.7% of alleles in PIN having mild/moderate methylation density compared to 5.5% in PIA and 11% in CaP. PIA and PIN lesions were enriched for methylation changes at 6 CpG sites that aligned with AP1 and SP1 binding sites. Among 16 PIN and CaP lesions with an overall intermediate level of methylation, 5 of the lesions had clones that clustered into either fully methylated or unmethylated. One patient with 3 CaP lesions displayed significant heterogeneity in methylation patterns: full, moderate, or no methylation across all clones in a given lesion. The results demonstrate that methylation density in the GSTP1 CpG island from PIN was intermediate between normal prostate epithelium/PIA and CaP lesions. The observed methylation in PIA and PIN was enriched at binding sites of key transcription factors, AP1 and SP1. The results are consistent with gradual spreading of DNA methylation centered at the transcription factor binding sites in the putative precursor lesions, with subsequent spreading of methylation across the entire CpG island in transition to CaP. Citation Format: Harshath Gupta, Hitoshi Inoue, Yasutomo Nakai, Masashi Nakayama, William G. Nelson, Angelo M. De Marzo, Srinivasan Yegnasubramanian. Progressive spreading of CpG methylation in the CpG island of Glutathione S-Transferase pi 1 (GSTP1) alleles across transitions from precursor to invasive prostate cancer [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 3734.

Oncogenic gene fusions in nonneoplastic precursors as evidence that bacterial infection can initiate prostate cancer

Prostate adenocarcinoma is the second most commonly diagnosed cancer in men worldwide, and the initiating factors are unknown. Oncogenic TMPRSS2:ERG (ERG+) gene fusions are facilitated by DNA breaks and occur in up to 50% of prostate cancers. Infection-driven inflammation is implicated in the formation of ERG+ fusions, and we hypothesized that these fusions initiate in early inflammation-associated prostate cancer precursor lesions, such as proliferative inflammatory atrophy (PIA), prior to cancer development. We investigated whether bacterial prostatitis is associated with ERG+ precancerous lesions in unique cases with active bacterial infections at the time of radical prostatectomy. We identified a high frequency of ERG+ non-neoplastic-appearing glands in these cases, including ERG+ PIA transitioning to early invasive cancer. These lesions were positive for ERG protein by immunohistochemistry and ERG messenger RNA by in situ hybridization. We additionally verified TMPRSS2:ERG genomic rearrangements in precursor lesions using tricolor fluorescence in situ hybridization. Identification of rearrangement patterns combined with whole-prostate mapping in three dimensions confirmed multiple (up to eight) distinct ERG+ precancerous lesions in infected cases. We further identified the pathogen-derived genotoxin colibactin as a potential source of DNA breaks in clinical cases as well as cultured prostate cells. Overall, we provide evidence that bacterial infections can initiate driver gene alterations in prostate cancer. In addition, our observations indicate that infection-induced ERG+ fusions are an early alteration in the carcinogenic process and that PIA may serve as a direct precursor to prostate cancer.

The current value of histological findings in negative prostate biopsies to predict the future risk of clinically significant prostate cancer

BackgroundRepeat prostate biopsy (PBx) is recommended under persistent suspicion of prostate cancer (PCa) or in the face of the following findings: atypical small acinar proliferation (ASAP); extense (≥3 biopsy sites) high-grade prostatic intraepithelial neoplasia (HGPIN); or HGPIN with atypical glands; suspicious for adenocarcinoma (PIN-ATYP). Nowadays; multiparametric magnetic resonance imaging (mpMRI) and mpMRI targeted PBx (MRI-TBx) are recommended in repeat PBx. Our objective was to analyze the current value of ASAP; mHGPIN; PIN-ATYP and other histological findings to predict clinically significant PCa (csPCa) risk. MethodsRetrospective analysis of 377 repeat PBxs. MRI-TBx was performed when Prostate Imaging-Reporting and Data System (PI-RADS) score >3 and 12-core transrectal ultrasound (TRUS) systematic PBx when ≤2. ASAP; HGPIN; mHGPIN; PIN-ATYP; and 8 other histological findings were prospectively reported in negative PBx. CsPCa was defined as ISUP group grade >2. ResultsIncidence of ASAP; multifocal HGPIN (mHGPIN) and PINATYP was 4.2%; 39.7% and 3.7% respectively; and csPCa rate was statistically similar among men with these histological findings. However; the rate of csPCa was 22.2% when proliferative inflammatory atrophy (PIA) was present; and 36.1% when it was not. PIA was the only histological finding which predicted lower risk of csPCa; with an OR of 0.54 (95%CI: 0.308−0.945; P = .031). In addition; PIA was an independent predictor of a model combining clinical variables and mpMRI which reached area under de ROC curve of 0.86 (95%CI: 0.83−0.90). ConclusionPIA emerged as the only predictive histological finding of csPCa risk and can contribute to a predictive model. mHGPIN failed to predict csPCa risk. The low incidence of ASAP (4.2%) and PIN-ATYP (3.7%) prevented us from drawing conclusions.

Valor actual de los hallazgos histológicos de biopsias de próstata negativas en la predicción del riesgo futuro de cáncer de próstata clínicamente significativo

IntroductionRepeat prostate biopsy (PBx) is recommended under persistent suspicion of prostate cancer (PCa) or in the face of the following findings: atypical small acinar proliferation (ASAP), extense (≥3 biopsy sites) high-grade prostatic intraepithelial neoplasia (HGPIN), or HGPIN with atypical glands, suspicious for adenocarcinoma (PIN-ATYP). Nowadays, multiparametric magnetic resonance imaging (mpMRI) and mpMRI targeted PBx (MRI-TBx) are recommended in repeat PBx. Our objective was to analyze the current value of ASAP, mHGPIN, PIN-ATYP and other histological findings to predict clinically significant PCa (csPCa) risk. MethodsRetrospective analysis of 377 repeat PBxs. MRI-TBx was performed when Prostate Imaging-Reporting and Data System (PI-RADS) score>3 and 12-core transrectal ultrasound (TRUS) systematic PBx when≤2. ASAP, HGPIN, mHGPIN, PIN-ATYP, and 8 other histological findings were prospectively reported in negative PBx. CsPCa was defined as ISUP group grade>2. ResultsIncidence of ASAP, multifocal HGPIN (mHGPIN) and PINATYP was 4.2%, 39.7% and 3.7% respectively, and csPCa rate was statistically similar among men with these histological findings. However, the rate of csPCa was 22.2% when proliferative inflammatory atrophy (PIA) was present, and 36.1% when it was not. PIA was the only histological finding which predicted lower risk of csPCa, with an OR of .54 (95% CI: .308-.945, P=.031). In addition, PIA was an independent predictor of a model combining clinical variables and mpMRI which reached area under de ROC curve of .86 (95% CI: .83-.90). ConclusionsPIA emerged as the only predictive histological finding of csPCa risk and can contribute to a predictive model. mHGPIN failed to predict csPCa risk. The low incidence of ASAP (4.2%) and PIN-ATYP (3.7%) prevented us from drawing conclusions.

Morphological and Molecular Characterization of Proliferative Inflammatory Atrophy in Canine Prostatic Samples.

Simple SummaryProstatic diseases are important worldwide, being the prostate cancer (PC) the most common tumor in men. Among the factors associated with PC development, the preneoplastic lesions are well-recognized. Preneoplastic lesions are cellular morphological alterations, induced by different factors and present a potential to progression for PC. In this scenario, dogs are considered spontaneous models. Dogs naturally develops prostatic hyperplasia, preneoplastic lesions and PC. Among the preneoplastic lesions, the proliferative inflammatory atrophy (PIA) develops spontaneously in dogs. PIA is an epithelial lesion induced by prostatic chronic inflammation, leading to a proliferative atrophy of the prostate gland. Thus, this study aimed to perform a full PIA morphological, phenotypical and molecular characterization in dogs. After reviewing the archives of the veterinary pathology service, it was identified 171 dogs containing PIA in the prostate gland, and among the PC cases (N = 84), it was identified PIA lesions surrounding 60.7% of PC cases. Besides that, we identified loss of genes related to the maintenance of prostatic tissue and can predispose to malignant transformation. Moreover, mutations in androgen receptor gene were identified, demonstration alteration in DNA in PIA. Overall, these results support the hypothesis that PIA can be considered a preneoplastic lesion in canine prostate.Proliferative inflammatory atrophy (PIA) is an atrophic lesion of the prostate gland that occurs in men and dogs and is associated with a chronic inflammatory infiltrate. In this study, we retrospectively reviewed canine prostatic samples from intact dogs, identifying 50 normal prostates, 140 cases of prostatic hyperplasia, 171 cases of PIA, 84 with prostate cancer (PC), 14 with prostatic intraepithelial neoplasia (PIN) and 10 with bacterial prostatitis. PIA samples were then selected and classified according to the human classification. The presence of PIA lesions surrounding neoplastic areas was then evaluated to establish a morphological transition from normal to preneoplastic and neoplastic tissue. In addition, the expression of PTEN, P53, MDM2 and nuclear androgen receptor (AR) were analyzed in 20 normal samples and 20 PIA lesions by immunohistochemistry and qPCR. All PIA lesions showed variable degrees of mononuclear cell infiltration around the glands and simple atrophy was the most common histopathological feature. PIA was identified between normal glands and PC in 51 (61%) out of the 84 PC samples. PIA lesions were diffusely positive for molecular weight cytokeratin (HMWC). Decreased PTEN and AR gene and protein expression was found in PIA compared to normal samples. Overall, our results strongly suggest that PIA is a frequent lesion associated with PC. Additionally, this finding corroborates the hypothesis that in dogs, as is the case in humans, PIA is a pre neoplastic lesion that has the potential to progress into PC, indicating an alternative mechanism of prostate cancer development in dogs.

Prediction of clinically significant prostate cancer after negative prostate biopsy: The current value of microscopic findings

ObjectiveTo assess the current ability of atypical small acinar proliferation (ASAP), multifocal high-grade prostatic intraepithelial neoplasia (mHGPIN), HGPIN with atypia (PINATYP) and other non-malignant lesions to predict clinically significant prostate cancer (csPCa) in repeat prostate biopsies. MethodsThis retrospective study analyzed 377 repeat prostate biopsies, carried out between 2.014 and 2.017, and excluding those with previous PCa or 5-alpha reductase inhibitors treatment. ASAP, mHGPIN, PINATYP, prostatic atrophy, prostatic hyperplastic atrophy, proliferative inflammatory atrophy (PIA), chronic prostatitis, acute prostatitis, or granulomatous prostatitis, were prospectively reported after 12-core transrectal ultrasound (TRUS) systematic negative previous biopsies. 3T-multiparametric magnetic resonance imaging (mpMRI) was performed previous repeat biopsies. At least 2-core TRUS targeted biopsies of Prostate Imaging-Reporting and Data Systemv2 lesions ≥3, and/or 12-core TRUS systematic biopsy were performed in repeat prostate biopsies. The main outcome measurements were csPCa detection, which was defined when the International Society of Uro-Pathology group grade >1 and avoided biopsies. After logistic regression analysis the most efficient model was selected, nomogram was designed with internal validation, and clinical utility was analyzed. ResultsNormal benign tissue alone was present in less than 2% of previous negative biopsies. mHGPIN (39.7%), ASAP (4.3%) and PINATYP (3.7%) failed to predict csPCa risk in repeat biopsies. The finding of PIA (38.2%) associated with a decreased the risk of csPCa with an Odd ratio of 0.54 (95% confidence interval: 0.31–0.95), P= 0.031. The area under the curve, to predict csPCa, of mpMRI was 0.736, increasing up to 0.860 (95% confidence internal:0.82–0.90) when PSA density, age, digital rectal examination, and differential PSA between biopsies and PIA finding were integrated in a predictive model. At 6% threshold, more than 20% of repeat prostate biopsies were saved without missing csPCa. ConclusionCurrently, mHGPIN in negative prostate biopsy seems not able to predict the risk of future csPCa. The low incidence of ASAP and PINATYP, in our series, did not allow us to draw conclusions. PIA finding associated with a reduced risk of csPCa, and it could be integrated in a useful based-mpMRI predictive nomogram.

Targeting Wistar rat as a model for studying benign, premalignant and malignant lesions of the prostate

AimsThe purpose of this study was to describe a suitable experimental model for studying aging-related prostate disorders including cancer. Materials and methods12-month old Wistar rats were kept in control conditions (n = 12) or treated (n = 16) for 6 months with Silastic implants filled with testosterone (T) and estradiol (E2). After the experiment period (at 18 months of age), animals were euthanized and the prostate and other organs were harvested, dissected, weighed, and processed for morphological, ultrastructural and molecular analyses. Key findingsWe demonstrated that male rats of Wistar strain nicely recapitulate the carcinogenesis process taking place in the aging prostate through the arising of benign, precancerous and malignant lesions, and above all yields a modest incidence of spontaneous PCa (~36%). Moreover, our results highlight that 100% incidence of PCa and precancerous lesions such as prostatic intraepithelial neoplasia and proliferative inflammatory atrophy were achieved in this rat strain after T + E2 treatment, without changing the broad spectrum of changes that naturally emerge in the prostate at advanced ages. Such enhancement of precancerous lesions and tumors was linked to a decreased expression of E-cadherin and β-catenin in parallel with an increase in Vimentin and N-cadherin, hallmark modifications of epithelial-mesenchymal transition. SignificanceOur findings provide solid evidence that aged Wistar rats may be an excellent model for studies regarding human prostate biology and related disorders including cancer.

E-Cadherin Downregulation is Mediated by Promoter Methylation in Canine Prostate Cancer.

E-cadherin is a transmembrane glycoprotein responsible for cell-to-cell adhesion, and its loss has been associated with metastasis development. Although E-cadherin downregulation was previously reported in canine prostate cancer (PC), the mechanism involved in this process is unclear. It is well established that dogs, besides humans, spontaneously develop PC with high frequency; therefore, canine PC is an interesting model to study human PC. In human PC, CDH1 methylation has been associated with E-cadherin downregulation. However, no previous studies have described the methylation pattern of CDH1 promoter in canine PC. Herein, we evaluated the E-cadherin protein and gene expression in canine PC compared to normal tissues. DNA methylation pattern was investigated as a regulatory mechanism of CDH1 silencing. Our cohort is composed of 20 normal prostates, 20 proliferative inflammatory atrophy (PIA) lesions, 20 PC, and 11 metastases from 60 dogs. The E-cadherin protein expression was assessed by immunohistochemistry and western blotting and gene expression by qPCR. Bisulfite- pyrosequencing assay was performed to investigate the CDH1 promoter methylation pattern. Membranous E-cadherin expression was observed in all prostatic tissues. A higher number of E-cadherin negative cells was detected more frequently in PC compared to normal and PIA samples. High-grade PC showed a diffuse membranous positive immunostaining. Furthermore, PC patients with a higher number of E-cadherin negative cells presented shorter survival time and higher Gleason scores. Western blotting and qPCR assays confirmed the immunohistochemical results, showing lower E-cadherin protein and gene expression levels in PC compared to normal samples. We identified CDH1 promoter hypermethylation in PIA and PC samples. An in vitro assay with two canine prostate cancer cells (PC1 and PC2 cell lines) was performed to confirm the methylation as a regulatory mechanism of E-cadherin expression. PC1 cell line presented CDH1 hypermethylation and after 5-Aza-dC treatment, a decreased CDH1 methylation and increased gene expression levels were observed. Positive E-cadherin cells were massively found in metastases (mean of 90.6%). In conclusion, low levels of E-cadherin protein, gene downregulation and CDH1 hypermethylation was detected in canine PC. However, in metastatic foci occur E-cadherin re-expression confirming its relevance in these processes.

Inflammation-associated pathologies in a case of prostate schistosomiasis: Implications for a causal role in prostate carcinogenesis.

Urogenital infection with Schistosoma haematobium is a risk factor for the development of squamous cell carcinoma of the urinary bladder. The pathophysiology is thought to be mediated in part by inflammation, cellular damage, and bladder regeneration induced by the parasitic infection. Herein, we report an unusual case of schistosomiasis of the prostate that was found concurrent with prostate adenocarcinoma in a radical prostatectomy specimen from a man in the United States. The infecting Schistosoma species was characterized via histomorphology and acid-fast stain. The concurrent Gleason score 6 prostate cancer was assessed for ETS transcription factor ERG (ERG), phosphatase and tensin homolog (PTEN), p27, and p53 status using immunohistochemistry (IHC). Cellular proliferation and the presence of intermediate cells in prostatic atrophy were assessed via immunostaining for Ki67 and CK903, respectively. Histomorphology and acid-fast stain of the infecting species were consistent with S. haematobium. We classified the Gleason score 6 prostate adenocarcinoma via IHC as ERG positive, PTEN intact, p27 intact, and without p53 nuclear accumulation. The prostatic epithelium immediately adjacent to the schistosomiasis-related granulomatous inflammation was atrophic and accompanied by increased cellular proliferation and the presence of intermediate cells. Upon literature review, we determined that prostate schistosomiasis is associated with a young age of prostate cancer diagnosis and highly aggressive prostate cancer. This is a rare case of prostate schistosomiasis in the United States; however, prostate schistosomiasis occurs frequently in endemic areas. The patient had traveled to a Schistosoma-endemic region, which was the likely location of exposure to the parasite. To our knowledge, this is the first report of the association of proliferative inflammatory atrophy and intermediate cells with schistosomiasis of the prostate. We propose that prostate schistosomiasis may be considered as a risk factor for the development of prostate cancer in geographic regions where Schistosoma species are endemic.

Chronic prostatitis alters the prostatic microenvironment and accelerates preneoplastic lesions in C57BL/6 mice

BackgroundChronic prostatitis has been supposed to be associated with preneoplastic lesions and cancer development. The objective of this study was to examine how chronic inflammation results in a prostatic microenvironment and gene mutation in C57BL/6 mice.MethodsImmune and bacterial prostatitis mouse models were created through abdominal subcutaneous injection of rat prostate extract protein immunization (EAP group) or transurethral instillation of uropathogenic E. coli 1677 (E. coli group). Prostate histology, serum cytokine level, and genome-wide exome (GWE) sequences were examined 1, 3, and 6 months after immunization or injection.ResultIn the EAP and E. coli groups, immune cell infiltrations were observed in the first and last months of the entire experiment. After 3 months, obvious proliferative inflammatory atrophy (PIA) and prostatic intraepithelial neoplasia (PIN) were observed accompanied with fibrosis hyperplasia in stroma. The decrease in basal cells (Cytokeratin (CK) 5+/p63+) and the accumulation of luminal epithelial cells (CK8+) in the PIA or PIN area indicated that the basal cells were damaged or transformed into different luminal cells. Hic1, Zfp148, and Mfge8 gene mutations were detected in chronic prostatitis somatic cells.ConclusionChronic prostatitis induced by prostate extract protein immunization or E. coli infection caused a reactive prostatic inflammation microenvironment and resulted in tissue damage, aberrant atrophy, hyperplasia, and somatic genome mutation.

Consequences of interleukin 1β-triggered chronic inflammation in the mouse prostate gland: Altered architecture associated with prolonged CD4+ infiltration mimics human proliferative inflammatory atrophy.

Elevated expression of the proinflammatory cytokine interleukin 1β (IL-1β) has been observed in expressed prostatic secretions of patients with chronic prostatitis/chronic pelvic pain syndrome, and genetic polymorphisms associated with the IL1B gene are linked to increased risk for aggressive prostate cancer. To study the role of IL-1β expression in prostate inflammation, we examined IL1B expression in human prostatic proliferative inflammatory atrophy (PIA) lesions and developed a tetracycline-regulated human IL1B transgene in the mouse prostate. Here, we demonstrate that IL1B expression is a common finding in human PIA lesions, which harbored focal IL1B expression in epithelial and stromal compartments. Human IL1B expression in the mouse prostate elicited acute and chronic inflammation. Penetrance and expressivity were variable and tunable by altering transgene dosage and the presence of an exogenous inducible marker antigen (green fluorescent protein). Inflammation was characterized by infiltration of CD4+ T cells, demonstrating an adaptive immune response. Chronic inflammation persisted after doxycycline (Dox) withdrawal. Reactive epithelia increased expression of downstream cytokines, and altered glandular architecture was observed upon sustained induction of IL1B. Immunohistochemical analyses revealed a higher proliferative index and decreased Nkx3.1 expression in inflamed mouse prostates. These data implicate IL-1β in human prostate pathology and this model provides a versatile platform to interrogate molecular mechanisms of inflammation-associated prostate pathologies associated with episodic or sustained IL-1β expression.

The Role of Chronic Inflammation in Prostate Carcinogenesis: A Follow-Up Study

Purpose To investigate the role of chronic inflammation in prostatic carcinogenesis with an emphasis on cancers of grade group 2 or above. Methods The presence/absence and extent of chronic inflammation and other relevant pathological findings were assessed using prostate needle biopsies obtained from patients with clinical parameters with suspicion of malignancy. In patients with no prior prostate cancer, follow-up biopsies were reviewed and correlated with the initial pathological findings. Results Of 1,006 prostate needle biopsy cases accessioned over 3 years at our institution, the initial biopsies of 244 cases were identified with no evidence of prostate cancer. These cases were divided into two subsets, including 202 cases with and 42 without chronic inflammation. Pathological findings assessed in this subset included post-atrophic hyperplasia, proliferative inflammatory atrophy, and high-grade prostatic intraepithelial neoplasia (HGPIN). Post-atrophic hyperplasia and proliferative inflammatory atrophy were noted only in patients with chronic inflammation. HGPIN was identified in 22 of the initial biopsy cases, specifically in 21 (10.3%) cases with inflammation and one case (2.4%) without inflammation. In follow-up biopsies, 70 patients (34.7%) with chronic inflammation were found to have prostatic adenocarcinoma with Gleason pattern 3 + 3 (42.9%; grade group 1), Gleason pattern 3 + 4(24.3%; grade group 2), Gleason pattern 4 + 3 (10%; grade group 3) and Gleason scores of 8 or higher (22.8%; grade groups 4 or 5), whereas cancer was found in 10 patients (23.8%) without chronic inflammation in the initial biopsy. Patients whose initial biopsies were benign and without inflammation did not show evidence of high-grade cancer (Gleason score of 8 or higher). Closely encroaching inflammation was observed more frequently in cancers of grade group 2 or above (76.5%, 13/17) compared with grade group 1 (50.0%, 3/6). Conclusions Our findings provide additional data supporting a role for chronic inflammation in the development of prostatic adenocarcinoma.

Immunophenotype of proliferative inflammatory atrophy (PIA) in the canine prostate

Immunophenotype of proliferative inflammatory atrophy (PIA) in the canine prostate

Immunoexpression of cell cycle regulators in canine prostate with proliferative lesions

Immunostaining of p21, p27, p53, cyclin D1, c-myc was evaluated in normal canine prostate and prostate with proliferative disorders to verify the interaction between these regulators of cell cycle progression. From 106 samples of canine prostate obtained from a TMA block, 15 were considered normal, 16 diagnosed as benign prostatic hyperplasia (BPH), 30 as proliferative inflammatory atrophy (PIA), 20 as prostatic intraepithelial neoplasia (PIN), and 25 as prostatic carcinoma (PC). There was positive correlation between p21 and p27 for number of stained cells and staining intensity in all conditions and between c-myc and p53 in prostates with PIN. Considering the number of labeled cells, there was positive correlation between p21 and p53 in the normal prostate. Relative to the intensity of staining, there was positive correlation between p21 and p53 in prostate tissue with PIN and between p27 and c-myc in prostates with PIA. A negative correlation between c-myc and cyclin D1 was also identified in the glands with PIN, considering the number of labeled cells, and between p27 and c-myc in the prostates with PC for staining intensity. In conclusion, the expression of p21, p27, p53, cyclin D1 and c-myc varies according to type of proliferative lesion in canine prostate. Taken together, the results indicate low growth potential of the canine PC in the presence of p21 and p27 overexpression, cyclin D1 low expression and regular expression of c-myc, even with the expression of p53 mutant type. Further, it was possible reaffirm the premalignant potential of PIA and PIN in canine prostate.