A working group classification of focal prostate atrophy lesions

Multiparametric MRI characteristics of prostatitis and atrophy in the peripheral zone in men without prostate cancer

PURPOSE

To analyse multiparametric magnetic resonance imaging (mpMRI) characteristics and appearance of histopathologically proven non-cancerous intraprostatic findings focussing on quantity of prostatitis and atrophy in the peripheral zone.

METHOD

In this retrospective analysis consecutive patients with mpMRI followed by MRI/TRUS-fusion biopsy comprising targeted (TB) and systematic biopsy (SB) cores without prostate cancer (PC) at histopathology were included. Subgroup analysis was performed in younger men (≤50 years). The proportions of prostatitis and atrophy were quantified for each biopsy core based on histopathology. MRI findings in the peripheral zone (PZ) and index lesions (IL, most suspicious/representative lesion) were characterized regarding changes in T2w, ADC value, and enhancement of dynamic contrast enhancement (DCE) and correlated with quantity of prostatitis and atrophy.

RESULTS

Seventy-two patients were analysed. The median baseline characteristics were PSA 5.4 ng/ml (4.0-7.9), PI-RADS classification 3 (2-4), prostate volume 43 ml (33-57), and PSA density 0.13 ng/ml2 (0.10-0.19). Prostatitis was found in 44 % (n = 32) and atrophy in 65 % (n = 47) of cases. The quantity of atrophy demonstrated a significant correlation to T2w changes, ADC increase and DCE enhancement (p = 0.05, p = 0.05, p = 0.01), whereas quantity of prostatitis did not show any significant correlation to the MRI changes (p = 0.68, p = 0.58, p = 0.95). Quantity of prostatitis and atrophy increased with PI-RADS classification. Younger men had lower PSA (4.4 vs. 7.8 ml/ng; p < 0.001), smaller prostate volume (40 vs. 59 ml; p = 0.001), and lower PI-RADS classification (2-3 vs. 3-4; p = 0.005) and prostatitis and atrophy were less frequently observed (p ≤ 0.01, p = 0.03).

CONCLUSIONS

Quantity of atrophy and prostatitis had different influence on MRI characteristics and increased within higher PI-RADS classification. Younger men had diffuse hypointense changes at T2w images, but less quantity of prostatitis and atrophy.

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.

Influence of Neighborhood Social and Natural Environment on Prostate Tumor Histology in a Cohort of Male Health Professionals

Adverse neighborhood social and natural (green space) environments may contribute to the etiology of prostate cancer (CaP), but mechanisms are unclear. We examined associations between neighborhood environment and prostate intratumoral inflammation in 967 men diagnosed with CaP with available tissue samples from 1986-2009 in the Health Professionals Follow-up Study. Exposures were linked to work or residential addresses in 1988. We estimated indices of neighborhood socioeconomic status (nSES) and segregation (Index of Concentration at the Extremes (ICE)) using US Census tract-level data. Surrounding greenness was estimated using seasonal averaged Normalized Difference Vegetation Index (NDVI) data. Surgical tissue underwent pathological review for acute and chronic inflammation, corpora amylacea, and focal atrophic lesions. Adjusted odds ratios (aORs) for inflammation (ordinal) and focal atrophy (binary) were estimated using logistic regression. No associations were observed for acute or chronic inflammation. Each interquartile-range increase in NDVI within 1,230 m of the participant's work or home address (aOR = 0.74, 95% confidence interval (CI): 0.59, 0.93), in ICE-income (aOR = 0.79, 95% CI: 0.61, 1.04), and in ICE-race/income (aOR = 0.79, 95% CI: 0.63, 0.99) was associated with lower odds of postatrophic hyperplasia. Interquartile-range increases in nSES (aOR = 0.76, 95% CI: 0.57, 1.02) and ICE-race/income (aOR = 0.73, 95% CI: 0.54, 0.99) were associated with lower odds of tumor corpora amylacea. Histopathological inflammatory features of prostate tumors may be influenced by neighborhood.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Immune Cell Proinflammatory Microenvironment and Androgen-Related Metabolic Regulation During Benign Prostatic Hyperplasia in Aging

To review the role of inflammation in the occurrence and development of benign prostatic hyperplasia (BPH), we searched PubMed for the latest published articles up to February 2021 using the following key words: "benign prostatic hyperplasia", "inflammation", "pathogenesis" and "disease development". Articles were obtained and reviewed to provide a systematic review of the current progress of the role of inflammation in the pathogenesis and progression of BPH. Inflammation contributes to the initiation and maintenance of unregulated cell proliferation and is closely related to the occurrence and development of BPH. Its action pathways include tissue damage and subsequent chronic healing, autoimmunity, and coaction with androgens. During the progression of inflammation, macrophages, interleukin-8 (IL-8), interleukin-1 (IL-1) and other inflammatory-related substances aggregate locally and cause BPH through various biochemical pathways. At the same time, BPH can also counteract inflammation to expand its scope and aggravate the situation. Inflammation can independently affect the development of BPH in a variety of ways, and it can also interact with androgens. In the course of treatment, early intervention in the occurrence and development of inflammation in prostate tissue can slow down the progression of BPH. The combination of standard therapies and anti-inflammatory measures may provide valuable new ideas for the treatment of BPH.

Health inequity drives disease biology to create disparities in prostate cancer outcomes

Prostate cancer exerts a greater toll on African American men than on White men of European descent (hereafter referred to as European American men): the disparity in incidence and mortality is greater than that of any other common cancer. The disproportionate impact of prostate cancer on Black men has been attributed to the genetics of African ancestry, to diet and lifestyle risk factors, and to unequal access to quality health care. In this Review, all of these influences are considered in the context of the evolving understanding that chronic or recurrent inflammatory processes drive prostatic carcinogenesis. Studies of inherited susceptibility highlight the contributions of genes involved in prostate cell and tissue repair (BRCA1/2, ATM) and regeneration (HOXB13 and MYC). Social determinants of health appear to accentuate these genetic influences by fueling prostate inflammation and associated cell and genome damage. Molecular characterization of the prostate cancers that arise in Black versus White men further implicates this inflammatory microenvironment in disease behavior. Yet, when Black and White men with similar grade and stage of prostate cancer are treated equally, they exhibit equivalent outcomes. The central role of prostate inflammation in prostate cancer development and progression augments the impact of the social determinants of health on disease pathogenesis. And, when coupled with poorer access to high-quality treatment, these inequities result in a disparate burden of prostate cancer on African American men.

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

Simple Summary

Prostatic 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.

Abstract

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.

Interchangeability of light and virtual microscopy for histopathological evaluation of prostate cancer

Virtual microscopy (VM) holds promise to reduce subjectivity as well as intra- and inter-observer variability for the histopathological evaluation of prostate cancer. We evaluated (i) the repeatability (intra-observer agreement) and reproducibility (inter-observer agreement) of the 2014 Gleason grading system and other selected features using standard light microscopy (LM) and an internally developed VM system, and (ii) the interchangeability of LM and VM. Two uro-pathologists reviewed 413 cores from 60 Swedish men diagnosed with non-metastatic prostate cancer 1998–2014. Reviewer 1 performed two reviews using both LM and VM. Reviewer 2 performed one review using both methods. The intra- and inter-observer agreement within and between LM and VM were assessed using Cohen’s kappa and Bland and Altman’s limits of agreement. We found good repeatability and reproducibility for both LM and VM, as well as interchangeability between LM and VM, for primary and secondary Gleason pattern, Gleason Grade Groups, poorly formed glands, cribriform pattern and comedonecrosis but not for the percentage of Gleason pattern 4. Our findings confirm the non-inferiority of VM compared to LM. The repeatability and reproducibility of percentage of Gleason pattern 4 was poor regardless of method used warranting further investigation and improvement before it is used in clinical practice.

Benign mimics of prostate cancer

The histopathological diagnosis of prostatic adenocarcinoma is challenged by the existence of numerous benign mimics. Most of these lesions have no clinical significance and many do not need to be reported. Their clinical relevance lies in the risk that they are misinterpreted as cancer. This review presents the histopathological features of benign mimics and discusses their distinction from cancer. The lesions that are most often misdiagnosed as cancer are atrophy and its variants, including simple atrophy, partial atrophy and post-atrophic hyperplasia. Benign proliferations are a group of lesions with crowded small glands with no or little nuclear atypia. The most problematic entity of this group is adenosis, which may have a more alarming architecture than some cancers. A diagnostic problem with atrophy and several of the benign proliferations is that the glands often have a discontinuous or absent basal cell layer. Hyperplastic and metaplastic lesions include basal cell hyperplasia. Basal cell hyperplasia may especially mimic prostate cancer with its small dark glands, variable nuclear atypia and a pseudoinfiltrative pattern, which may be present. The anatomical structure that most often causes diagnostic problems is the seminal vesicle. The mucosa of the seminal vesicle contains small acini, often with very pronounced nuclear atypia that may be misinterpreted as cancer. Pathologists need to be familiar with these mimics, as a false positive diagnosis of prostate cancer may lead to unnecessary radical treatment.

Atrophic and Microcystic Limited Prostatic Adenocarcinomas

Atrophic carcinoma and microcystic carcinoma have previously been classified as variants of conventional acinar adenocarcinoma. In this article, we studied 4 cases of atrophic carcinoma and 4 cases of limited microcystic carcinoma. We found an incidence of 0.8% in 250 needle prostatic biopsies and 1.3% of atrophic carcinoma in 150 radical prostatectomies. Microcystic carcinomas were found in 3 prostatectomies (1.2%) and in 1 needle biopsy (0.67%). The useful histological criteria for atrophic carcinoma included the irregular disposition of the glands, infiltrative pattern, "rigid" luminal borders, and intraluminal secretions. Cytological changes included scant cytoplasm, nucleomegaly, hyperchromatic nuclei, and visible nucleoli. The glands of the microcystic carcinoma differ from the benign glands because the malignant ones show a markedly greater dilatation and exhibit rigidity of glandular lumens. In some cases of microcystic carcinoma, the nuclei were flattened, small, and hyperchromatic; therefore, they can be difficult to recognize as malignant.

A Prospective Study of Intraprostatic Inflammation, Focal Atrophy, and Progression to Lethal Prostate Cancer

BACKGROUND

Inflammation and focal atrophy are common features adjacent to prostate tumors. Limited evidence exists on whether these features have prognostic significance.

METHODS

In the Health Professionals Follow-Up Study and Physicians' Health Study, we studied 1,035 men diagnosed with prostate cancer. A genitourinary pathologist centrally reviewed tumor and normal areas of hematoxylin and eosin slides from prostate cancer specimens for the presence of acute and chronic inflammation, and four subtypes of focal atrophy. Cox proportional hazards models adjusted for potential confounders were used to estimate HRs and 95% confidence intervals (CI) for the association of these features with lethal prostate cancer, defined as development of metastatic disease or death during follow-up.

RESULTS

During a median of 12 years of follow-up, 153 men developed lethal prostate cancer. A total of 84% of men had histologic evidence of chronic inflammation and 30% had acute inflammation. Both chronic and acute inflammation were inversely associated with lethal prostate cancer in age- and lifestyle-adjusted models. Chronic inflammation remained inversely associated with lethal prostate cancer after additionally adjusting for prognostic clinical features (HR = 0.45; 95% CI, 0.30-0.69 for mild and HR = 0.51; 95% CI, 0.33-0.80 for moderate to severe). None of the atrophic lesions were associated with lethal prostate cancer.

CONCLUSIONS

Our data suggest that the presence of inflammation, particularly chronic inflammation, in prostate cancer tissue is associated with better prognosis among patients with prostate cancer.

IMPACT

This is the largest prospective cohort study to examine the association between inflammation, focal atrophy, and lethal prostate cancer.

In Search for risk predictors at the microscopic scenario of a negative biopsy. A systematic review

INTRODUCTION

In cases of persistent suspicion of prostate cancer (PC), repeat prostate biopsies (PB) are frequently performed in spite of their low yield. In the context of a negative PB, there is a microscopic scenario (MS), which we define as the group of recognizable non-neoplastic lesions. While some of these lesions seem to have a protective effect, the existence of others increases the risk of PC detection in posterior PB. The objective of this systematic review is to identify the lesions that may belong to the MS of a negative PB and analyse the current evidence of their association with the risk of detecting PC in subsequent PBs.

EVIDENCE ACQUISITION

Two independent reviewers conducted a literature search on Medline, Embase and Central Cochrane with the following search terms: small acinar proliferation, ASAP, prostatic intraepithelial neoplasia, HGPIN, adjacent small atypical glands, pinatyp, atrophy, proliferative inflammatory atrophy, pia, prostatic inflammation, prostatitis and prostate cancer. 1,015 references were first identified, and 57 original articles were included in the study, following the PRISMA declaration and the PICO selection principles.

EVIDENCE SYNTHESIS

Atypical small acinar proliferation is associated with PC detection in repeat PB with rates ranging between 32 and 48%. High-grade prostatic intraepithelial neoplasia (HGPIN) is related to PC in 13 to 42% of cases. Studies show that HGPIN, when multifocal, is a significant independent risk factor for PC. Prostatic atrophy, inflammatory proliferative atrophy and prostatic inflammation seem to act as protective factors on the detection of PC in repeat PB. On the other hand, the risk of PC detection reduces significantly in male patients with multifocal HGPIN and coexistent PIA.

CONCLUSIONS

The MS of a negative PB may include atypical small acinar proliferation, HGPIN, prostatic atrophy, inflammatory proliferative atrophy and prostatic inflammation lesions, since they all seem to be associated with the risk of PC detection in repeat PB. This review has led us to create the hypothesis that the MS of a negative PB might be a valuable and useful tool when considering repeat PB.

Three-dimensional architecture of common benign and precancerous prostate epithelial lesions

Aims

Many glandular lesions can mimic prostate cancer microscopically, including atrophic glands, adenosis and prostatic intraepithelial neoplasia. While the characteristic histopathological and immunohistochemical features of these lesions have been well established, little is known about their three‐dimensional architecture. Our objective was to evaluate the three‐dimensional organisation of common prostate epithelial lesions.

Methods and results

500 μm‐thick punches (n = 42) were taken from radical prostatectomy specimens, and stained with antibodies targeting keratin 8–18 and keratin 5 for identification of luminal and basal cells, respectively. Tissue samples were optically cleared in benzyl alcohol:benzyl benzoate and imaged using a confocal laser scanning microscope. The three‐dimensional architecture of peripheral and transition zone glands was acinar, composed of interconnecting and blind‐ending saccular tubules. In simple atrophy, partial atrophy and post‐atrophic hyperplasia, the acinar structure was attenuated with branching blind‐ending tubules from parental tubular structures. Three‐dimensional imaging revealed a novel variant of prostate atrophy characterised by large Golgi‐like atrophic spaces parallel to the prostate surface, which were represented by thin, elongated tubular structures on haematoxylin and eosin (H&E) slides. Conversely, adenosis lacked acinar organisation, so that it closely mimicked low‐grade prostate cancer. High‐grade prostatic intraepithelial neoplasia displayed prominent papillary intraluminal protrusions but retained an acinar organisation, whereas intraductal carcinoma predominantly consisted of cribriform proliferations with either spheroid, ellipsoid or complex interconnecting lumens.

Conclusions

While various prostate epithelial lesions might mimic malignancy on H&E slides, their three‐dimensional architecture is acinar and clearly different from the tubular structure of prostate cancer, with adenosis as an exception.

The Genomics of Prostate Cancer: A Historic Perspective

The genomics of prostate cancer (PCA) has been difficult to study compared with some other cancer types for a multitude of reasons, despite significant efforts since the early 1980s. Overcoming some of these obstacles has paved the way for greater insight into the genomics of PCA. The advent of high-throughput technologies coming from the initial use of microsatellite and oligonucleotide probes gave rise to techniques like comparative genomic hybridization (CGH). With the introduction of massively parallel genomic sequencing, referred to as next-generation sequencing (NGS), a deeper understanding of cancer genomics in general has occurred. Along with these technologic advances, there has been the development of computational biology and statistical approaches to address novel large data sets characterized by single base resolution. This review will provide a historic perspective of PCA genomics with an emphasis on the cardinal mutations and alterations observed to be consistently seen in PCA for both hormone-naïve localized PCA and castration-resistant prostate cancer (CRPC). There will be a focus on alterations that have the greatest potential to play a role in disease progression and therapy management.

The association of atrophy in baseline prostate biopsy and lower prostate cancer grade in radical prostatectomy specimens

INTRODUCTION

To evaluate whether the presence of prostate atrophy (P.A.) in negative prostate biopsy is associated with prostate cancer (P.C.a) grade at surgical pathology among men who are ultimately diagnosed with P.C.a and undergo radical prostatectomy (R.P.).

METHODS

A retrospective analysis was performed of 136 men from the placebo arm of the Reduction by Dutasteride of P.C.a Events (R.E.D.U.C.E.) trial who had a baseline prostate biopsy negative for P.C.a, and were later diagnosed with P.C.a on biopsy and underwent radical prostatectomy over the 4-year study period. The association of baseline P.A. (present/absent) with P.C.a grade (W.H.O./I.S.U.P. grade group 1 or ≥2) at surgical pathology was evaluated with logistic regression in uni- and multivariable analyses, controlling for baseline patient characteristics.

RESULTS

P.A. was observed in 74 prostate biopsies (54%). P.A. was not associated with baseline characteristics (age, body mass index, prostate-specific antigen level, prostate volume, race, family history of P.C.a, and digital rectal exam), except for chronic inflammation (p = 0.001). The presence of P.A. in baseline prostate biopsies was associated with lower risk of W.H.O./I.S.U.P. grade group ≥2 P.C.a in R.P. specimens on both univariable (O.R. = 0.39, 95% C.I. = 0.19-0.78, p = 0.008) and multivariable (O.R. = 0.43, 95% C.I. = 0.20-0.92, p = 0.029) analyses.

CONCLUSIONS

Among men with a baseline prostate biopsy negative for P.C.a who were later found to have P.C.a and underwent R.P., baseline P.A. is independently associated with lower risk of W.H.O./I.S.U.P. grade group ≥2 P.C.a on surgical pathology. P.A. may be used to identify subjects at lower risk for W.H.O./I.S.U.P. ≥ 2 P.C.a and select optimal candidates for active surveillance.

Computer vision detects subtle histological effects of dutasteride on benign prostate

OBJECTIVE

To determine whether a computer vision-based approach applied to haematoxylin and eosin (H&E) prostate biopsy images can distinguish dutasteride-treated tissue from placebo, and identify features associated with degree of responsiveness to 5α-reductase inhibitor (5ARI) therapy.

SUBJECTS AND METHODS

Our study population comprised 100 treatment-adherent men without prostate cancer assigned to dutasteride or placebo in the REDUCE trial, who had slides available from mandatory year-4 biopsies. Half of the men also provided slides from a year-2 biopsy. We obtained 20× whole-slide images and used specialized software to generate a library of 1 300 epithelial and stromal features from objects comprising superpixels and several types of nuclei, including spatial relations among objects between and within each hierarchical level. We used penalized logistic regression and fivefold cross-validation to find optimal combinations of histological features in the year-4 biopsies. Feature data from the year-2 biopsies were fitted to a final model for independent validation. Two pathologists, blinded to treatment, scored each image for focal atrophy and histological features previously linked to 5AR1 treatment.

RESULTS

Consensus classification by pathologists obtained a discrimination accuracy equivalent to chance. A 21-feature computer vision model gave a cross-validation area under the curve of 0.97 (95% confidence interval [CI] 0.95-0.99) in the year-4 biopsies and 0.79 (95% CI: 0.65-0.92) in the set-aside year-2 biopsies. Histology scores were not correlated with change in prostate-specific antigen level, serum dihydrotestosterone level or gland volume. Key features associated with dutasteride treatment included greater shape and colour uniformity in stroma, irregular clustering of epithelial nuclei, and greater variation in lumen shape.

CONCLUSION

The present findings show that a computer vision approach can detect subtle histological effects attributable to dutasteride, resulting in a continuous measure of responsiveness to the drug that could eventually be used to predict individual patient response in the context of BPH treatment or cancer chemoprevention.

FOXP3+ regulatory T cells in normal prostate tissue, postatrophic hyperplasia, prostatic intraepithelial neoplasia, and tumor histological lesions in men with and without prostate cancer

BACKGROUND

The tumor promoting or counteracting effects of the immune response to cancer development are thought to be mediated to some extent by the infiltration of regulatory T cells (T_regs ). In the present study we evaluated the prevalence of T_reg populations in stromal and epithelial compartments of normal, post atrophic hyperplasia (PAH), prostatic intraepithelial neoplasia (PIN), and tumor lesions in men with and without prostate cancer.

METHODS

Study subjects were 102 men consecutively diagnosed with localized prostate cancer undergoing radical prostatectomy and 38 men diagnosed with bladder cancer undergoing cystoprostatectomy without prostate cancer at the pathological examination. Whole mount sections from all patients were evaluated for the epithelial and stromal expression of CD4⁺ T_regs and CD8⁺ T_regs in normal, PAH, PIN, and tumor lesions. A Friedmańs test was used to investigate differences in the mean number of T_regs across histological lesions. Logistic regression was used to estimate crude and adjusted odds ratios (OR) for prostate cancer for each histological area.

RESULTS

In men with prostate cancer, similarly high numbers of stromal CD4⁺ T_regs were identified in PAH and tumor, but CD4⁺ T_regs were less common in PIN. Greater numbers of epithelial CD4+ T_regs in normal prostatic tissue were positively associated with both Gleason score and pT-stage. We observed a fourfold increased risk of prostate cancer in men with epithelial CD4⁺ T_regs in the normal prostatic tissue counterpart.

CONCLUSIONS

Our results may suggest a possible pathway through which PAH develops directly into prostate cancer in the presence of CD4⁺ T_regs and indicate that transformation of the anti-tumor immune response may be initiated even before the primary tumor is established.

Benign mimics of prostatic adenocarcinoma

Benign mimics present either as common challenges in daily routine practice or may cause diagnostic dilemmas because some are less commonly seen and one may be less familiar in recognizing them. There are a multitude of mimics of prostatic adenocarcinoma, which may represent normal gland structures, benign proliferations, atrophic lesions, hyperplastic or metaplastic changes, and inflammatory processes. Some of them are preferentially found in certain anatomic areas of the prostate, either confined to the prostate, or outside of the gland. Various benign mimics of prostatic carcinoma may be also evaluated based on their morphologic similarity to Gleason patterns 3-5 of prostatic adenocarcinoma. Most of the mimics are easily recognizable in larger specimens, such as TUR of the prostate or radical prostatectomy specimens, but they may pose diagnostic problems when the evaluation is done on limited tissue, such as needle-core biopsies or if prostate specimens are infrequently encountered in practice. Therefore, before signing out a report with a diagnosis of prostatic carcinoma, pathologists should carefully consider and rule out the various benign lesions that may mimic carcinoma. This is particularly relevant in the current prostate biopsy practice which relies on using extended biopsy core templates. The awareness and familiarity with the characteristic features of the mimics and judicial use of additional ancillary tests, including immunohistochemistry can prevent overdiagnosis and false-positive interpretation. This review provides a contemporary update on the broad spectrum of the benign prostatic lesions that can mimic prostate adenocarcinoma, outlines their key morphologic and immunohistochemical diagnostic features, and provides a diagnostic, pattern-based approach in establishing a correct diagnosis and distinguishing them reliably from prostatic adenocarcinoma.

CXXC5 expression in prostate cancer: implications for cancer progression

Identification of genes specifically deregulated in prostate adenocarcinoma may lead to discovery of new oncogenes/tumour suppressors with clinical relevance for diagnosis, prognosis and/or therapy. CXXC5 is a gene encoding a retinoid-inducible nuclear factor, whose overexpression in breast tumours, metastatic malignant melanomas and papillary thyroid carcinoma has been recently reported. We previously found differential expression of CXXC5 transcripts in metastatic prostate cancer cell lines of both rat and human origin. However, knowledge on the expression of this gene in benign or malignant human prostate tissue is lacking. The aim of this study was to determine the mRNA and protein expression pattern of CXXC5 in human benign prostate tissue, proliferative inflammatory atrophy, high-grade prostatic intra-epithelial neoplasia and prostate cancer, using qPCR, chromogenic in situ hybridization and immunohistochemistry. Our results showed that protein levels determined by immunohistochemistry were in agreement with transcript levels observed by chromogenic in situ hybridization. CXXC5 mRNA and protein expressions were significantly higher in prostate cancer, high-grade prostatic intra-epithelial neoplasia, and proliferative inflammatory atrophy, compared to benign prostate tissue. Significantly, within the same tissue specimens, CXXC5 staining was stronger in malignant acini than in matched adjacent, benign acini; immunostaining for this protein was mainly localized to the nucleus of benign epithelial cells and both the nucleus and cytoplasm of malignant epithelial cells. Our findings suggest that CXXC5 may play a role in the process of prostate carcinogenesis. Additional studies are required to determine the biological and clinical significance of CXXC5 in prostate cancer development and/or progression.

Correlation between ERG Fusion Protein and Androgen Receptor Expression by Immunohistochemistry in Prostate, Possible Role in Diagnosis and Therapy

Background: Recent discovery of gene rearrangements have brought a new look to the molecular pathogenesis of cancer. Gene fusions occur in nearly 60% of prostate adenocarcinoma, being the TMPRSS2-ERG one of the most common. Evidence supports the role of ERG fusion in tumorigenesis, progression and invasion via effecting pathways such as WNT, MYC, uPA, PI3K/AKT/PTEN, RAS/RAF/MAPF, NKX3.1, GST-pi and androgen receptor (AR) mediated signaling. Most of the ERG fusions involve 5'-partners androgen responsive. Therefore, we aimed to evaluate AR and ERG fusion protein expression on prostate tissue to find clinicopathological applications and possible role in therapy.

Methods: One hundred three samples, including prostate core biopsies and radical prostatectomy specimens, were evaluated for ERG and AR expression by immunohistochemistry (IHC). ERG rearrangement was done by fluorescence in situ hybridization (FISH) on 11 randomly selected cases and correlated with IHC results.

Results: From the total of 103 samples, eight (8/103) were benign, fourteen (14/103) had atypical glands, two (2/103) had prostatic intraepithelial neoplasia (PIN), and seventy nine (79/103) showed prostate adenocarcinoma. Forty four (44/79) tumor cases were Gleason score (GS) 6-7 (lower GS), and thirty five (35/79) were GS of 8-10 (higher GS). ERG immunoreaction was observed in 27.8% (22/79) of the tumor cases, showing higher expression in those with lower GS (68.2%, 15/22) compared to higher GS (31.8%, 7/22). Neither benign glands nor PIN stained with ERG. AR expression was observed in 75% of benign samples, 78.5% of atypical glands, 100% of PIN, and in 87.3% of tumor cases with no significant difference based on GS. Co-expression of ERG and AR was evaluated on all the tumor samples. ERG+/AR+ was seen in 77.3% (17/22) of the ERG+ tumor cases, with higher frequency in lower GS (64.7%, 11/17) compared to those with higher GS (35.3%, 6/17). All but five corresponding ERG+ tumor samples were negative for AR. Only 5 samples were ERG-/AR- corresponding to adenocarcinoma GS of 6. Presence or absence of ERG rearrangement was confirmed by FISH and correlated with IHC results.

Conclusions: Characterization of ERG status by IHC in prostate tissue has an excellent correlation with FISH. It may also assist in diagnosis since none of the benign glands stained with ERG. Co-expression of ERG+/AR+ in prostate tumor by IHC may suggest gene fusion between ERG and a 5'-partner driven by androgen signaling such as TMPRSS2, which it could represent an important ancillary test for clinical management and development of new therapeutic targets.

Clinical Significance of Proliferative Inflammatory Atrophy in Negative Prostatic Biopsies

PURPOSE

To analyze the association between prostatic proliferative inflammatory atrophy finding in negative prostate biopsies and future detection of prostate cancer (PCa) and its aggressiveness in men subjected to repeat biopsies, due to persistent suspicion of PCa.

MATERIALS AND METHODS

Prospective and observational study of 474 men scheduled to repeated PBs. Assessment of PIA and its extension in the previous biopsy. PCa detection rate and tumor aggressiveness. Age, serum total PSA, free PSA, percent free PSA (%fPSA), digital rectal exam (DRE), prostate volume (PV), PSA density (PSAD), PSA kinetics (PSAV and PSADT) findings of PIA and HGPIN, and number of affected cores in previous PBs were included in the univariate and multivariate analysis. Aggressive tumors were considered when any Gleason pattern 4 was found.

RESULTS

PCa was detected in 133 men (28.1%). Age, serum total PSA, %fPSA, PV, PSAD, PSAV, PSADT, and PIA finding were significantly associated to PCa detection. However, only age, OR: 1.06 (95%CI: 1.03-1.10), P < 0.01; DRE, OR: 1.76 (95%CI: 1.05-2.92), P = 0.03; %fPSA, OR: 0.96 (95%CI: 0.93-0.99), P = 0.03; PV, OR: 0.98 (95%CI: 0.97-0.99) and PIA finding, OR: 0.49 (95%CI: 0.29-0.83), P < 0.01, were independent predictors of PCa detection. PCa was found in 18% of 159 men with previous PIA finding while in 33% of 315 men without previous PIA (P < 0.01). None of the studied parameters including PIA in the previous biopsy were related with subsequent PCa aggressiveness.

CONCLUSIONS

PIA finding in negative biopsies correlates with a decreased frequency of detecting PCa in men with persistent suspicion of PCa. The aggressiveness of future detected tumors was not associated with previous PIA finding. Prostate 76:1501-1506, 2016. © 2016 Wiley Periodicals, Inc.

A Phase II Randomized Trial of Lycopene-Rich Tomato Extract Among Men with High-Grade Prostatic Intraepithelial Neoplasia

A diverse body of evidence suggests that lycopene might inhibit prostate cancer development. We conducted a 6-mo repeat biopsy randomized trial among men with high-grade prostatic intraepithelial neoplasia (HGPIN). Here we report results for serum lycopene, prostate specific antigen (PSA) and insulin-like growth factor (IGF) proteins, histopathological review, and tissue markers for proliferation [minichromosome maintenance protein 2 (MCM-2)] and cell cycle inhibition (p27). Participants consumed placebo or tomato extract capsules containing 30 mg/day lycopene. Pre- and posttreatment biopsies were immunostained and digitally scored. Serum lycopene was determined by LC-MS-MS. In secondary analyses, pathologists blindly reviewed each biopsy to score histological features. Fifty-eight men completed the trial. Serum lycopene increased 0.55 μmol/L with treatment and declined 0.29 μmol/L with placebo. We observed no meaningful differences in PSA, IGF-1, or IGF binding protein 3 concentrations between groups, nor any differences in expression of MCM-2 or p27 in epithelial nuclei. Prevalences of cancer, HGPIN, atrophy, or inflammation posttreatment were similar; however, more extensive atrophy and less extensive HGPIN was more common in the lycopene group. Despite large differences in serum lycopene following intervention, no treatment effects were apparent on either the serum or benign tissue endpoints. Larger studies are warranted to determine whether changes observed in extent of HGPIN and focal atrophy can be replicated.

The benign mimickers of prostatic acinar adenocarcinoma

As the most frequent malignant histological subtype in prostatic cancer, prostatic acinar adenocarcinoma (PAA) has a series of benign mimickers including prostatic or non-prostatic lesions and normal structures, which may lead to an erroneous diagnosis and inappropriate treatment. It is very important to be aware of the existence of these mimickers and to recognize their histological features. The differential diagnosis should be based on a comprehensive evaluation of clinical history, histological structure, cytological morphology and the results of immunohistochemistry (IHC) staining, rather than on single criteria (e.g., the presence of prominent nucleoli or basal cell layer).

Clinical significance of proliferative inflammatory atrophy finding in prostatic biopsies

BACKGROUND

Proliferative inflammatory atrophy (PIA) has been involved in prostatic carcinogenesis. However, little is known about the clinical significance of a PIA finding in prostatic biopsies (PBs). The aim of this study is to determine the incidence of prostate inflammatory atrophy (PIA) in prostate biopsies (PBs), its association to high-grade prostatic intraepithelial neoplasia (HGPIN), prostate cancer (PCa), and tumor aggressiveness.

METHODS

Prospective and observational study of PIA lesion in 528 extended PBs and 200 radical prostatectomy specimens (RPS).

OUTCOME MEASUREMENTS

PIA, HGPIN, PCa incidence, Gleason score, clinical and pathologic tumor stage and insignificant tumor rate. Univariate and multivariate analysis.

RESULTS

Overall incidence of PIA and HGPIN was 30.3% and 54%. In RPS, the incidence was 30.5% and 72%, respectively. No significant association was found between PIA and HGPIN. Overall PCa detection rate in PBs was 38.1%. PCa was found in 27.5% PBs with PIA and 42.7% of those without PIA, P < 0.001. In contrast, PCa was detected in 50.9% of PBs with HGPIN and 23% of those without HGPIN, P = 0.001. Multivariate analysis revealed that PIA decreased the risk of PCa, OR:0.59 (95%CI:0.37-0.95), P = 0.029, while HGPIN increased OR:3.16 (95%CI:2.04-4.90), P = 0.001. PIA was not related to Gleason grade and clinical stage, however it was associated to an insignificant tumors increase, OR:3.08 (95%CI:1.09-8.7), P = 0.033. The information in RPS suggests that PIA is associated with less aggressive tumors and a higher probability of insignificant tumors.

CONCLUSIONS

PIA is present in one third of PBs, HGPIN in one half of them, and no association exists between both lesions. Contrary to HGPIN, PIA finding is associated to lower risk of PCa detection. Tumors accompanying PIA seem to be less aggressive and have a greater probability of being insignificant.

Baseline Prostate Atrophy is Associated with Reduced Risk of Prostate Cancer in Men Undergoing Repeat Prostate Biopsy

PURPOSE

We evaluated whether the presence and severity of baseline prostate atrophy in men with initial biopsy negative for prostate cancer was associated the risk of subsequent prostate cancer detection in a clinical trial with scheduled study mandated biopsies.

MATERIALS AND METHODS

We retrospectively analyzed the records of 3,084 men 50 to 75 years old with prostate specific antigen between 2.5 and 10 ng/ml, and a prior negative biopsy in the placebo arm of the REDUCE (Reduction by Dutasteride of Prostate Cancer Events) study who completed at least 1 per-protocol biopsy. Prostate cancer (defined as present or absent) and prostate atrophy (graded as absent, mild or moderate/marked) was assessed by central pathology review. The association of baseline atrophy with positive 2 and 4-year repeat biopsies was evaluated with logistic regression, controlling for baseline covariates.

RESULTS

Baseline prostate atrophy was detected in 2,143 men (70%) and graded as mild and moderate/marked in 1,843 (60%) and 300 (10%) baseline biopsies, respectively. Patients with atrophy were older and had a larger prostate, and more acute and chronic prostate inflammation. At 2-year biopsy the prostate cancer incidence was 17% (508 cases). Baseline atrophy was significantly associated with lower prostate cancer risk (univariable and multivariable OR 0.60, 95% CI 0.50-0.74 and OR 0.67, 95% CI 0.54-0.83, p <0.001, respectively) at the 2-year biopsy. These results were similar at the 4-year biopsy (univariable and multivariable OR 0.70, 95% CI 0.53-0.93 and OR 0.72, 95% CI 0.53-0.97, p = 0.03, respectively). Relative to no atrophy the prostate cancer risk at the 2-year repeat biopsy was lower for mild atrophy (OR 0.69, 95% CI 0.55-0.86) and moderate/marked atrophy (OR 0.51, 95% CI 0.34-0.76, each p <0.001).

CONCLUSIONS

Baseline prostate atrophy in men with a prostate biopsy negative for prostate cancer was independently associated with subsequent lower prostate cancer detection.

Prostate volume index and chronic inflammation of the prostate type IV with respect to the risk of prostate cancer

BACKGROUND

Benign prostatic hyperplasia and prostate cancer (PCA) alter the normal growth patterns of zonal anatomy with changes of prostate volume (PV). Chronic inflammatory infiltrates (CII) type IV are the most common non-cancer diagnosis of the prostate after biopsy.

OBJECTIVE

To evaluate associations of both PV index (PVI), i.e. the ratio of transitional zone volume (TZV) to peripheral zone volume (PZV), and CII with PCA in patients undergoing biopsy.

SUBJECTS AND METHODS

Between January 2007 and December 2008, 268 consecutive patients who underwent prostate biopsy were retrospectively evaluated. PV and TZV were measured by transrectal ultrasound. PZV was computed by subtracting the PV from the TZV. CII were evaluated according to standard criteria. Significant associations of PVI and the presence of CII (CII+) with PCA risk were assessed by statistical methods.

RESULTS AND LIMITATIONS

We evaluated 251 patients after excluding cases with painful rectal examinations, prostate-specific antigen (PSA) >20 μg/ml and metastases. The PCA detection rate was 41.1%. PVI was a negative independent predictor of PCA. A PVI ≤1.0 was directly [odds ratio (OR) = 2.36] associated with PCA, which was detected more frequently in patients with a PVI ≤1.0 (29.1%) than in those with a PVI >1.0 (11.9%). CII+ was inversely (OR = 0.57) and independently associated with PCA, which was detected less frequently in cases with CII (9.9%) than in those without CII (21.1%). Potential study limitations might relate to the fact that PV was not measured by prostatectomy specimens and there was PSA confounding for CII and PCA.

CONCLUSIONS

Low values of PVI are directly associated with risk of PCA, which was almost 2.5 times higher in patients with a PVI ≤1.0. The PVI might be an effective parameter for clustering patients at risk of PCA. CII+ was inversely associated with risk of PCA and decreased the probability of detecting PCA by 43%. The role of the PVI and CII in PCA carcinogenesis needs further research.

Clinical significance of proliferative inflammatory atrophy in prostate biopsy

INTRODUCTION

Proliferative inflammatory atrophy (PIA) is a frequently observed lesion in prostate biopsies and some authors have postulated its involvement in prostate carcinogenesis. However, the mechanisms that would permit its neoplastic transformation and the clinical significance of its finding in a prostate biopsy is currently not well known.

OBJECTIVE

To analyze the characteristics of the PIA lesion, its possible role in prostate carcinogenesis and its relation with the tumor aggressiveness.

MATERIAL AND METHOD

A systematic review was made of the literature in PubMed with the terms «proliferative inflammatory atrophy» or «PIA» and «prostate.» The most important findings are summarized in accordance with the study objective.

RESULTS

PIA seems to be involved in prostate carcinogenesis. This hypothesis is based on its frequent association to cancer lesions (CaP) and on some genetic alterations that are common to the high grade prostatic intraepithelial neoplasia (HGPIN) and to the CaP, fundamentally deficit in GSTP1 expression and overexpression of AGR2. Currently, there are no epidemiological studies that evaluate the incidence of PIA or its association with HGPIN and CaP. Only one study, carried out by our group, has determined the global incidence of PIA in 30% of the prostate biopsies, a lower association to CaP than the HGPIN lesion and an association between PIA and tumors of lower and insignificant grade.

CONCLUSIONS

PIA shares genetic alterations with HGPIN and CaP. Currently, there is no epidemiologic evidence to consider that the PIA is associated to a greater incidence of CaP and the genetic and epidemiological data available suggest its association to not very aggressive tumors.

The diet as a cause of human prostate cancer

Asymptomatic prostate inflammation and prostate cancer have reached epidemic proportions among men in the developed world. Animal model studies implicate dietary carcinogens, such as the heterocyclic amines from over-cooked meats and sex steroid hormones, particularly estrogens, as candidate etiologies for prostate cancer. Each acts by causing epithelial cell damage, triggering an inflammatory response that can evolve into a chronic or recurrent condition. This milieu appears to spawn proliferative inflammatory atrophy (PIA) lesions, a type of focal atrophy that represents the earliest of prostate cancer precursor lesions. Rare PIA lesions contain cells which exhibit high c-Myc expression, shortened telomere segments, and epigenetic silencing of genes such as GSTP1, encoding the π-class glutathione S-transferase, all characteristic of prostatic intraepithelial neoplasia (PIN) and prostate cancer. Subsequent genetic changes, such as the gene translocations/deletions that generate fusion transcripts between androgen-regulated genes (such as TMPRSS2) and genes encoding ETS family transcription factors (such as ERG1), arise in PIN lesions and may promote invasiveness characteristic of prostatic adenocarcinoma cells. Lethal prostate cancers contain markedly corrupted genomes and epigenomes. Epigenetic silencing, which seems to arise in response to the inflamed microenvironment generated by dietary carcinogens and/or estrogens as part of an epigenetic "catastrophe" affecting hundreds of genes, persists to drive clonal evolution through metastatic dissemination. The cause of the initial epigenetic "catastrophe" has not been determined but likely involves defective chromatin structure maintenance by over-exuberant DNA methylation or histone modification. With dietary carcinogens and estrogens driving pro-carcinogenic inflammation in the developed world, it is tempting to speculate that dietary components associated with decreased prostate cancer risk, such as intake of fruits and vegetables, especially tomatoes and crucifers, might act to attenuate the ravages of the chronic or recurrent inflammatory processes. Specifically, nutritional agents might prevent PIA lesions or reduce the propensity of PIA lesions to suffer "catastrophic" epigenome corruption.

Preneoplasia in the prostate gland with emphasis on high grade prostatic intraepithelial neoplasia

There are a variety of morphological patterns and processes that have been implicated in the pathogenesis of prostate cancer. Prostatic intraepithelial neoplasia (PIN), inflammation with or without atrophy, and adenosis (atypical adenomatous hyperplasia) have all been given candidate status as precursor lesions of prostatic adenocarcinoma. Based on decades of research, high grade prostatic intraepithelial neoplasia (HPIN), a proliferative lesion of prostatic secretory cells, has emerged as the most likely morphological pre-invasive lesion involved in the evolution of many but not all prostatic adenocarcinomas. In this manuscript, we briefly discuss other proposed precursors of prostatic adenocarcinoma and then focus on the history, diagnostic criteria and morphology of HPIN. The incidence of HPIN and its relationship to prostate cancer is reviewed. The differential diagnosis of large glandular patterns in the prostate is discussed in depth. Finally, we summarise the recent clinicopathological studies evaluating the clinical significance of HPIN and discuss follow-up strategies in men diagnosed with HPIN.

[Benign mimickers of the prostate cancer. Diagnostic challenges]

The diagnosis of prostate cancer (PCa), especially limited adenocarcinoma on needle biopsy, is often challenging. Before making diagnosis of PCa, it is prudent for the pathologist to consider different benign patterns that may lead to a false positive interpretation. Histoanatomic structures such as seminal vesicles, Cowper's glands and paraganglia along with hyperplasia, atrophy with its different patterns and adenosis may generate difficulties in differential diagnosis. Furthermore, inflammatory processes and post-treatment changes may cause problems. The above entities can in some instances simulate low-grade and less commonly high grade PCa. Knowledge of these patterns and application of appropriate immunohistochemistry will lead the pathologist to a correct diagnosis.

[Non-neoplastic alterations of the prostate. Why should pathologists know them?]

Non-neoplastic changes in the prostatic gland include inflammatory, atrophic, hyperplastic and metaplastic reaction patterns of the glandular epithelium and the fibromuscular stroma. Furthermore, histoanatomical structures from outside the prostatic gland are sometimes included in biopsy material. Knowledge of the morphological appearance of benign, reactive lesions is important in order to differentiate them from malignancies. To this aim knowing the precise location of tissue sampling as well as ancillary immunohistochemical investigations are often useful or necessary.

Topographic and quantitative relationship between prostate inflammation, proliferative inflammatory atrophy and low-grade prostate intraepithelial neoplasia: a biopsy study in chronic prostatitis patients

Inflammatory processes are important components in the pathogenesis of many human cancers. According to the 'injury and regeneration' model for prostate carcinogenesis, injury caused by pathogens or pro-inflammatory cytotoxic agents would trigger proliferation of prostatic glandular cells, leading to the appearance of epithelial lesions named 'Proliferative Inflammatory Atrophy' (PIA). Inflammatory cells infiltrating the prostate would release genotoxic reactive oxygen species, leading atrophic cells to neoplastic progression. The hypothesis pointing to PIA as risk-lesion for prostate cancer has been extensively investigated at the cellular and molecular levels, but few morphological data are available linking PIA or prostatic intraepithelial neoplasia (PIN) to inflammation or clinical prostatitis. We investigated at the morphological level 1367 prostate biopsies from 98 patients with a recent history of chronic prostatitis, and 32 patients with biopsies positive for carcinoma. Our results show that i) PIA is found more frequently in biopsy cores containing a severe or moderate inflammatory focus, compared to NON-PIA lesions (partial or cystic atrophy); ii) the PIA lesion post-atrophic hyperplasia is more frequently found in tissues showing mild or no inflammation; iii) the extent of PIA per patient correlates with the burden of moderate or severe inflammation, whereas NON-PIA lesions do not; iv) low-grade PIN is in over 90% of cases emerging from normal, non-atrophic glands and is more frequently found in biopsy cores with absent or mild inflammatory burden; v) the inverse relationship between the prevalence of low-grade PIN and the extent of PIA lesions per patient is described by a power law function, suggesting the low likelihood of the concomitant presence of these lesions in the same tissue; vi) NON-PIA lesions correlate inversely with neoplasia in patients with prostate cancer; vii) the total scores of the NIH-CPSI questionnaire correlate with both PIA and inflammation burdens at diagnosis of prostatitis but not after pharmacological intervention. These results point to a positive association between tissue inflammation, clinical prostatitis and the putative cancer risk-lesion PIA, but do not support a model whereby low-grade PIN would arise from PIA.

Nonneoplastic lesions of the prostate and bladder

CONTEXT

Specimens from the prostate and bladder are commonly encountered by the general surgical pathologist. Emphasis is usually placed on neoplasms of the bladder and prostate, particularly if malignant, owing to their therapeutic consequences. A good command of benign lesions occurring in the bladder and prostate, and knowledge of their preneoplastic potential will help pathologists confidently diagnose malignancy versus its benign mimickers and guide the urologists in choosing the appropriate therapy and follow-up for the patient.

OBJECTIVE

To present a mixture of benign entities, and discuss their histologic and clinical characteristics, hoping to provide a practical review for the general surgical pathologist.

DATA SOURCES

An extensive review of the literature on the entities discussed was performed.

CONCLUSIONS

A wide variety of benign entities are present in the prostate and bladder. Benign lesions in the prostate can be age related, such as prostatic atrophy and benign prostatic hyperplasia; transition zone associated, such as basal cell hyperplasia, adenosis, and sclerosing adenosis; or prostatic urethra associated. Benign lesions of the bladder encompass a wide variety of reactive changes that can occur in the urothelium, as well as hyperplastic lesions or reactive proliferations that could be misdiagnosed as malignant. The bladder responds to chronic irritation through several reactive/metaplastic lesions such as cystitis cystica/glandularis, keratinizing squamous metaplasia, or nephrogenic metaplasia. The urothelium can also give rise to hyperplastic/proliferative lesions, in particular von Brunn nest hyperplasia, papillary polypoid cystitis, and pseudocarcinomatous proliferation, which should be distinguished from malignant processes. Ectopic tissue, such as prostatic or mullerian, can also be seen.

The spectrum of morphology in non-neoplastic prostate including cancer mimics

The spectrum of morphology in non-neoplastic prostate includes lesions of prostatic epithelial origin, the most common being atrophy, including partial atrophy, adenosis (atypical adenomatous hyperplasia), basal cell hyperplasia and crowded benign glands, as well as those of non-prostatic origin, such as seminal vesicle epithelium. These lesions often mimic lower-grade prostatic adenocarcinoma whereas others, such as granulomatous prostatitis, for example, are in the differential diagnosis of adenocarcinoma, Gleason grades 4 or 5. Diagnostic awareness of the salient histomorphological and relevant immunohistochemical features of these prostatic pseudoneoplasms is critical to avoid rendering false positive diagnoses of malignancy.

Inflammation and prostate carcinogenesis

Quite a few epidemiological studies including meta-analyses indicate that prostate inflammation is associated with increased risk of prostate cancer. The cause of inflammation in the prostate is speculated to be several microorganisms that cause prostatitis or sexually transmitted infections. Other specific microorganisms, such as xenotropic murine leukemia virus-related virus, are also reported to relate to the development of prostate cancer; however, the contribution of this microorganism to prostate cancer development needs to be carefully interpreted. Environmental factors, especially dietary factors, might also be associated with prostate cancer development. Among related dietary factors, charred meat carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine might be a link between environmental factors and inflammation, because 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine has the potential to accelerate prostate inflammation through its estrogenic effect. In light of these findings, preventing or reducing prostate inflammation might be one strategy for chemoprevention of prostate cancer.

Inflammation and preneoplastic lesions in benign prostate as risk factors for prostate cancer

Benign changes ranging from atrophy and inflammation to high-grade prostatic intraepithelial neoplasia (HGPIN) are common findings on prostate core needle biopsies. Although atrophy and inflammation may be precursors of prostate cancer, only HGPIN is currently recommended to be included in surgical pathology reports. To determine whether these benign findings increase prostate cancer risk, we conducted a case-control study nested within a historical cohort of 6692 men with a benign prostate specimen collected between 1990 and 2002. The analytic sample included 574 case-control pairs comprised of cases diagnosed with prostate cancer a minimum of 1 year after cohort entry and controls matched to cases on date and age at cohort entry, race, and type of specimen. The initial benign specimen was reviewed for presence of HGPIN, atrophy (simple, lobular, and partial) and inflammation (glandular and/or stromal). HGPIN significantly increased risk for prostate cancer (odds ratio (OR)=2.00; 95% confidence interval (CI)=1.25-3.20). Inflammation within the stromal compartment was associated with decreased risk (OR=0.66; CI=0.52-0.84), and diffuse stromal inflammation of severe grade had the strongest inverse association with risk (OR=0.21; CI=0.07-0.62). In a model adjusted for prostate-specific antigen (PSA) level at cohort entry and inflammation, simple atrophy was associated with a 33% increased prostate cancer risk that was marginally significant (P=0.03). Clinicians should consider patterns and extent of inflammation when managing high-risk patients with negative biopsy results. Identifying benign inflammatory processes that underlie high PSA levels would help to reduce the number of unnecessary repeated prostate biopsies.

Gene expression profiles and differential cytoglobin expression in atrophy and adenocarcinoma of the prostate

BACKGROUND

Proliferative inflammatory atrophy (PIA) has been proposed as a potential precursor for prostate cancer. The precise molecular abnormalities in prostatic atrophy compared to high-grade prostatic intraepithelial neoplasia (HGPIN) and carcinoma have not been fully defined.

METHODS

We utilized laser capture microdissection and microarray analysis to characterize cells of PIA, HGPIN, invasive prostatic carcinoma, and non-atrophic benign prostatic epithelium (NABE). Cytoglobin was selected for immunohistochemistry (IHC) validation. IHC stains were evaluated for proportion of positive glands, and intensity of cytoglobin staining. An immunoreactive score (IR score) was determined as the product of the percentage of positive staining and intensity.

RESULTS

Microarray analysis revealed probe sets that separated the microdissected cell types. Several genes showed overlapping expression patterns between PIA and PIN, and HGPIN and invasive carcinoma. Cytoglobin protein expression was detected in 57/93 (61%) of NABE and BPH cases, 92/93 atrophy (99%), 3/34 (9%) of PIN, and 23/61 carcinoma (37%) samples. The highest IHC scores were calculated for atrophy foci. A subset (33%) of atrophy cases showed the same low-cytoglobin expression level as PIN and carcinoma.

CONCLUSIONS

Prostatic epithelium can be stratified into normal, atrophic, PIN, and invasive carcinoma categories based on differential genetic signatures. Cytoglobin, a protein that can be induced in response to oxidative stress, was elevated in most atrophy foci, suggesting hypoxic, and/or oxidative damage. The lower level of cytoglobin seen in neoplastic cells and 33% of atrophy foci may indicate a shared susceptibility to oxidative damage for this subset of atrophy cases and prostatic neoplasia.

Selected common diagnostic problems in urologic pathology: perspectives from a large consult service in genitourinary pathology

CONTEXT

Several common differential diagnoses are encountered in urologic pathology, frequently causing patient referrals for a second opinion.

OBJECTIVES

To review 3 common differential diagnoses encountered in a large consultation service in genitourinary pathology, including partial atrophy versus prostatic acinar adenocarcinoma, oncocytoma versus chromophobe renal cell carcinoma, and urothelial carcinoma in situ versus normal urothelium and reactive atypia. We will discuss the detailed, morphologically distinctive features and the usefulness of immunohistochemistry.

DATA SOURCES

Personal experience and review of the current literature.

CONCLUSIONS

Careful morphologic assessment and awareness of diagnostic pitfalls are fundamental in reaching a definitive diagnosis in most cases. Immunohistochemistry is useful but should be used only in conjunction with the morphologic impression.

Dietary carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine-induced prostate carcinogenesis in CYP1A-humanized mice

To develop a relevant mouse model for prostate cancer prevention research, we administered a dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), to CYP1A-humanized mice. In comparison with mouse Cyp1a2, human CYP1A2 preferentially activates PhIP to a proximate carcinogen. Following a single oral dose of PhIP (200 mg/kg body weight), we observed inflammation, atrophy of acini, low-grade prostatic intraepithelial neoplasia (PIN; after 20 weeks), and high-grade PIN (HgPIN; after 30 to 50 weeks) in dorsolateral, ventral, and coagulating anterior prostate glands of these mice. These lesions were androgen receptor positive and featured the loss of expression of the basal cell marker p63 and the tumor suppressor PTEN. Similar to human prostate carcinogenesis, glutathione S-transferase P1 (GSTP1) expression was lost or partially lost in HgPIN. E-Cadherin expression was also lost in HgPIN. The expression of DNA methyltransferase 1 was elevated, possibly to enhance promoter hypermethylation for the silencing of GSTP1 and E-cadherin. Prostate carcinogenesis was promoted by a high-fat stress diet, resulting in HgPIN that developed earlier and in advanced lesions displayed features consistent with carcinoma in situ. This dietary carcinogen-induced prostate cancer model, recapitulating important features of early human prostate carcinogenesis, constitutes a new experimental system for prostate cancer research.

ETS rearrangements in prostate cancer

Prostate cancer is a clinically and molecularly heterogeneous disease. Understanding the biologic underpinning of prostate cancer is necessary to best determine how biology is associated with the risk of disease progression and how this understanding might provide insight into the development of novel therapeutic approaches. The focus of this review is on the recently identified common ETS and non-ETS gene rearrangements in prostate cancer. Although multiple molecular alterations have been detected in prostate cancer, a basic understanding of gene fusion prostate cancer should help explain the clinical and biologic diversity, providing a rationale for a molecular subclassification of the disease.

Inflammation, focal atrophic lesions, and prostatic intraepithelial neoplasia with respect to risk of lethal prostate cancer

BACKGROUND

A challenge in prostate cancer (PCa) management is identifying potentially lethal disease at diagnosis. Inflammation, focal prostatic atrophy, and prostatic intraepithelial neoplasia (PIN) are common in prostate tumor specimens, but it is not clear whether these lesions have prognostic significance.

METHODS

We conducted a case-control study nested in a cohort of men diagnosed with stage T1a-b PCa through transurethral resection of the prostate in Sweden. Cases are men who died of PCa (n = 228). Controls are men who survived more than 10 years after PCa diagnosis without metastases (n = 387). Slides were assessed for Gleason grade, inflammation, PIN, and four subtypes of focal prostatic atrophy: simple atrophy (SA), postatrophic hyperplasia (PAH), simple atrophy with cyst formation, and partial atrophy. We estimated OR and 95% CI for odds of lethal PCa with multivariable logistic regression.

RESULTS

Chronic inflammation and PIN were more frequently observed in tumors with PAH, but not SA. No specific type of atrophy or inflammation was significantly associated with lethal PCa overall, but there was a suggestion of a positive association for chronic inflammation. Independent of age, Gleason score, year of diagnosis, inflammation, and atrophy type, men with PIN were 89% more likely to die of PCa (95% CI: 1.04-3.42).

CONCLUSION

Our data show that PIN, and perhaps presence of moderate or severe chronic inflammation, may have prognostic significance for PCa.

IMPACT

Lesions in tumor adjacent tissue, and not just the tumor itself, may aid in identification of clinically relevant disease.