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

Sodium butyrate alleviates experimental autoimmune prostatitis by inhibiting oxidative stress and NLRP3 inflammasome activation via the Nrf2/HO-1 pathway

BACKGROUND

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) leads to severe discomfort in males and loss of sperm quality. Current therapeutic options have failed to achieve satisfactory results. Sodium butyrate (NaB) plays a beneficial role in reducing inflammation, increasing antioxidant capacities, and improving organ dysfunction; additionally NaB has good safety prospects and great potential for clinical application. The purpose of the current research was to study the effect of NaB on CP/CPPS and the underlying mechanisms using a mouse model of experimental autoimmune prostatitis (EAP) mice.

METHODS

The EAP mouse model was successfully established by subcutaneously injecting a mixture of prostate antigen and complete Freund's adjuvant. Then, EAP mice received daily intraperitoneal injections of NaB (100, 200, or 400 mg/kg/day) for 16 days, from Days 26 to 42. We then explored anti-inflammatory potential mechanisms of NaB by studying the effects of Nrf2 inhibitor ML385 and HO-1 inhibitor zinc protoporphyrin on prostate inflammation and pelvic pain using this model. On Day 42, hematoxylin-eosin staining and dihydroethidium staining were used to evaluate the histological changes and oxidative stress levels of prostate tissues. Chronic pelvic pain was assessed by applying Von Frey filaments to the lower abdomen. The levels of inflammation-related cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor were detected by enzyme-linked immunosorbent assay. The regulation of Nrf2/HO-1 signaling pathway and the expression of NLRP3 inflammasome-related protein in EAP mice were detected by western blot analysis assay.

RESULTS

Compared with the EAP group, chronic pain development, histological manifestations, and cytokine levels showed that NaB reduced the severity of EAP. NaB treatment could inhibit NLRP3 inflammasome activation. Mechanism studies showed that NaB intervention could alleviate oxidative stress in EAP mice through Nrf2/HO-1 signal pathway. Nrf2/HO-1 pathway inhibitors can inhibit NaB -mediated oxidative stress. The inhibitory effect of NaB on the activation of NLRP3 inflammasome and anti-inflammatory effect can also be blocked by Nrf2/HO-1 pathway.

CONCLUSIONS

NaB treatment can alleviates prostatic inflammation and pelvic pain associated with EAP by inhibiting oxidative stress and NLRP3 inflammasome activation via the Nrf2/HO-1 pathway. NaB has the potential as an effective agent in the treatment of EAP.

Resolvin D1 Attenuates Inflammation and Pelvic Pain Associated with EAP by Inhibiting Oxidative Stress and NLRP3 Inflammasome Activation via the Nrf2/HO-1 Pathway

Background

Resolvin D1 (RvD1), a member of the specialized pro-resolving lipid mediators family, has a potent anti-inflammatory effect and alleviates tissue damage. The purpose of the current research was to study the effect of RvD1 on CP/CPPS and the underlying mechanisms using a mouse model of experimental autoimmune prostatitis (EAP) mice.

Materials and Methods

The EAP mouse model was successfully established, and was used to test the therapeutic effect of RvD1. Hematoxylin-eosin staining and dihydroethidium staining were used to evaluate the histological changes and oxidative stress levels of prostate tissues. Chronic pelvic pain was assessed by applying von Frey filaments to the lower abdomen. The superoxide dismutase enzyme and malondialdehyde levels were detected using enzyme-linked immunosorbent assay (ELISA). The levels of inflammation-related cytokines, including IL-1β, IL-6, and TNF-α were detected by ELISA.

Results

RvD1 treatment ameliorated prostatic inflammation and the pelvic pain of EAP mice. RvD1 treatment could inhibit activation of the NLRP3 inflammasome and oxidative stress. RvD1 treatment could activate Nrf2/HO-1 signaling in mice with EAP. Blockade of Nrf2/HO-1 signaling abolished the RvD1-mediated inhibition of oxidative stress, NLRP3 inflammasome activation and the anti-inflammatory effect of RvD1 in EAP.

Conclusion

RvD1 treatment can reduce inflammatory cell infiltration in prostate tissue and attenuate pelvic pain associated with EAP by inhibiting oxidative stress and NLRP3 inflammasome activation via the Nrf2/HO-1 pathway. These results provide new insights that RvD1 has the potential as an effective agent in the treatment of EAP.

Inflammation and Prostate Cancer: Pathological Analysis from Pros-IT CNR 2

BACKGROUND

Extensive research effort has been devoted to investigating the link between inflammation and PCa. However, this relationship remains unclear and controversial. The aim of our multi-center study was to investigate this association by histologically evaluating the distribution of PI and PCA in prostate biopsy cores from patients of eight referral centers in Italy.

RESULTS

We evaluated 2220 cores from 197 patients; all the frustules were re-evaluated by dedicated pathologists retrospectively. Pathologists assigned IRANI scores and determined the positions of PIs; pathologists also re-evaluated the presence of PCa and relative ISUP grade. PCa was recorded in 749/2220 (33.7%). We divided this sample into a PCa PI group (634/749 cores [84.7%]) and a non-PCa + PI group (1157/1471 cores [78.7%]). We observed a statistically significant difference in the presence of inflammation among cores with cancer (p < 0.01). Moreover, periglandular inflammation was higher in the cores with neoplasia, while stromal inflammation was higher in cores without neoplasia (38.5% vs. 31.1% and 55.4% vs. 63.5% p < 0.01).

CONCLUSIONS

In our experience, there is evidence of an association between PI and PCa at a tissue level. Further studies are needed to confirm our findings and to identify patients who might benefit from target therapies to prevent PCa occurrence and/or progression.

The secret identities of TMPRSS2: Fertility factor, virus trafficker, inflammation moderator, prostate protector and tumor suppressor

The human TMPRSS2 gene is pathogenetically implicated in both coronaviral lung infection and prostate cancer, suggesting its potential as a drug target in both contexts. SARS-COV-2 spike polypeptides are primed by the host transmembrane TMPRSS2 protease, triggering virus fusion with epithelial cell membranes followed by an endocytotic internalisation process that bypasses normal endosomal activation of cathepsin-mediated innate immunity; viral co-opting of TMPRSS2 thus favors microbial survivability by attenuating host inflammatory responses. In contrast, most early hormone-dependent prostate cancers express TMPRSS2:ERG fusion genes arising from deletions that eliminate the TMPRSS2 coding region while juxtaposing its androgen-inducible promoter and the open reading frame of ERG, upregulating pro-inflammatory ERG while functionally disabling TMPRSS2. Moreover, inflammatory oxidative DNA damage selects for TMPRSS2:ERG-fused cancers, whereas patients treated with antiinflammatory drugs develop fewer of these fusion-dependent tumors. These findings imply that TMPRSS2 protects the prostate by enabling endosomal bypass of pathogens which could otherwise trigger inflammation-induced DNA damage that predisposes to TMPRSS2:ERG fusions. Hence, the high oncogenic selectability of TMPRSS2:ERG fusions may reflect a unique pro-inflammatory synergy between androgenic ERG gain-of-function and fusogenic TMPRSS2 loss-of-function, cautioning against the use of TMPRSS2-inhibitory drugs to prevent or treat early prostate cancer.

Macrophages expedite cell proliferation of prostate intraepithelial neoplasia through their downstream target ERK

The risk factors for prostate cancer include a high-fat diet and obesity, both of which are associated with an altered cell environment including increased inflammation. It has been shown that chronic inflammation due to a high-fat diet or bacterial infection has the potential to accelerate prostate cancer as well as its precursor, prostatic intraepithelial neoplasia (PIN), development. However, the underlying mechanism of how chronic inflammation promotes prostate cancer development, especially PIN, remains unclear. In this study, we showed that more macrophages were present in PIN areas as compared to the normal areas of human prostate. When co-culturing PIN cells with macrophages in 3D, more PIN cells had nuclear localized cyclin D1, indicating that macrophages enhanced PIN cell proliferation. We identified ICAM-1 and CCL2 as chemoattractants expressed by PIN cells to recruit macrophages. Furthermore, we discovered that macrophage-secreted cytokines including C5a, CXCL1, and CCL2 were responsible for increased PIN cell proliferation. These three cytokines activated ERK and JNK signaling in PIN cells through a ligand-receptor interaction. However, only blockade of ERK abolished macrophage cytokines-induced cell proliferation of PIN. Overall, our results provide a mechanistic view on how macrophages activated through chronic inflammation can expedite PIN progression during prostate cancer development. The information from our work can facilitate a comprehensive understanding of prostate cancer development, which is required for improvement of current strategies for prostate cancer therapy.

Application of Anti-Inflammatory Agents in Prostate Cancer

Chronic inflammation is a major cause of human cancers. The environmental factors, such as microbiome, dietary components, and obesity, provoke chronic inflammation in the prostate, which promotes cancer development and progression. Crosstalk between immune cells and cancer cells enhances the secretion of intercellular signaling molecules, such as cytokines and chemokines, thereby orchestrating the generation of inflammatory microenvironment. Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play pivotal roles in inflammation-associated cancer by inhibiting effective anti-tumor immunity. Anti-inflammatory agents, such as aspirin, metformin, and statins, have potential application in chemoprevention of prostate cancer. Furthermore, pro-inflammatory immunity-targeted therapies may provide novel strategies to treat patients with cancer. Thus, anti-inflammatory agents are expected to suppress the “vicious cycle” created by immune and cancer cells and inhibit cancer progression. This review has explored the immune cells that facilitate prostate cancer development and progression, with particular focus on the application of anti-inflammatory agents for both chemoprevention and therapeutic approach in prostate cancer.

Advances in research on the interaction between inflammation and cancer

Inflammation is the body's response to cell damage. Cancer is a general term that describes all malignant tumours. There are no confirmed data on cancer-related inflammation, but some research suggests that up to 50% of cancers may be linked to inflammation, which has led to the concept of ‘cancer-associated inflammation’. Although some cancer patients do not appear to have a chronic inflammatory background, there might be inflammatory cell infiltration in their cancer tissues. The continuation of the inflammatory response plays an important role in the initiation, promotion, malignant transformation, invasion and metastasis of cancer. Anti-inflammatory therapy has been shown to have some effects on the prevention and treatment of cancer, which supports a pathogenic relationship between inflammation and cancer. This review describes the interaction between inflammation and tumour development and the main mechanism of regulation of the inflammatory response during tumour development.

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.

CDKN1B Val 109 Gly variant is not related to risk of prostate cancer

Association between CDKN1B gene Val 109 Gly polymorphism and prostate cancer (PCa) susceptibility has been investigated in several studies but with inconsistent conclusions. We adopted odds ratios (ORs) and 95% confidence intervals (CIs) to assess the correlation between CDKN1B Val 109 Gly variant and PCa susceptibility. Moreover, we used in-silico tools to evaluate the relationship of CDKN1B expression and overall survival (OS) or disease free survival (DFS) time in PCa patients. The overall results demonstrated no association of the CDKN1B variant on PCa risk [allelic contrast (OR = 0.78, 95% CI = 0.45 - 1.35, P_{heterogeneity}  = 0.038); GV vs VV (OR = 0.83, 95% CI = 0.56 - 1.25, P_{heterogeneity}  = 0.253); GG vs VV (OR = 0.48, 95% CI = 0.23 - 1.01, P_{heterogeneity}  = 0.161); GG+GV vs VV (OR = 0.75, 95% CI = 0.52 -1.08, P_{heterogeneity}  = 0.132) and GG vs GV+VV (OR = 0.63, 95% CI = 0.25 - 1.11, P_{heterogeneity}  = 0.152)]. In subgroup analysis by ethnicity and source of control, we also identified similar results. In-silico results showed that expression of CDKN1B was decreased in PCa tissue, especially in less advanced PCa (Gleason score = 6 or 7). No significant difference of OS or DFS time was indicated between the low and high expression of CDKN1B. Our present study showed evidence that CDKN1B Val 109 Gly variant is not related to PCa risk. Future studies with large sample size are needed to confirm this correlation in more details.

Association between oral pathogens and prostate cancer: building the relationship

BACKGROUND

Chronic inflammation and infections are associated with increased risk of prostate cancer development. There is considerable evidence that proves the interrelationship between bacterial/viral infections and carcinogenesis. Periodontitis is a chronic inflammatory disease triggered by gram-negative anaerobic bacteria. In this narrative review, we investigate the relationship between periodontal disease and prostate cancer by reviewing previous studies of the association and possible mechanisms that may explain this link.

METHODS

A comprehensive search for articles published was performed using the key words, "periodontal disease", "prostate disease", "prostate cancer", "prostatic inflammation". Thorough reviews of each study were conducted and assessed for eligibility, and data was summarized.

RESULTS

The role of inflammatory responses in the prostate as drivers of malignancy appears to be predisposed by periodontal pathogens and/or periodontitis inflammatory mediators.

CONCLUSION

Periodontal diseases might be associated with prostate cancer. However, the mechanism(s) explaining this relationship remains unclear and requires further elucidation.

Potential repositioning of GV1001 as a therapeutic agent for testosterone‑induced benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is one of the leading causes of male reproductive disorders. Therapeutic agents currently in use have severe side effects; therefore, alternative drugs that exhibit improved therapeutic activity without side effects are required. The present study investigated the protective effect of GV1001 against testosterone‑induced BPH in rats. BPH in castrated rats was established via daily subcutaneous (s.c.) injections of testosterone propionate (TP, 3 mg/kg) dissolved in corn oil for 4 weeks. GV1001 (0.01, 0.1 and 1 mg/kg, s.c.) was administered 3 times per week for 4 weeks, together with TP (3 mg/kg) injection. The rats were sacrificed on the last day of treatment, and their prostates were excised and weighed for biochemical and histological studies. Serum levels of testosterone and dihydrotestosterone (DHT) were also measured. In rats with TP‑induced BPH, a significant increase in prostate weight (PW) and prostatic index (PI), accompanied by a decrease in antioxidant enzyme activity, was observed. Histological studies revealed clearly enlarged glandular cavities in rats with BPH. GV1001 (0.01 and 0.1 mg/kg) treatment significantly decreased PW and PI in rats with TP‑induced BPH. In addition, GV1001 demonstrated a potent inhibitory effect on 5α‑reductase in prostate. The present data suggest that the protective role of GV1001 against testosterone‑induced BPH is closely associated with its antioxidant potential. Additional studies are required to identify the mechanisms by which GV1001 protects against BPH to determine its clinical application.

Association of a common genetic variant in RNASEL and prostate cancer susceptibility

The RNASEL gene (2’, 5’-oligoisoadenylate synthetase-dependent) encodes a ribonuclease that plays a significant role in the apoptotic and antiviral activities of interferons. Various studies have used polymorphisms in the RNASEL gene to evaluate prostate cancer risk but studies that show an association between RNASEL Arg462Gln (1385G>A, R462Q, rs486907) polymorphism and prostate cancer risk are somewhat inconclusive. To assess the impact of RNASEL Arg462Gln polymorphism on prostate cancer risk, we conducted a meta-analysis of all available studies including 11,522 patients and 10,976 control subjects. The overall results indicated no positive association between the variant and prostate cancer risk. However, in a subgroup analysis by ethnicity, obvious associations were observed in Hispanic Caucasians for allelic contrast (OR = 1.18, 95% CI = 1.00 - 1.39, P_{heterogeneity} = 0.010), homozygote comparison (OR = 1.50, 95% CI = 1.02 – 2.20, P_{heterogeneity} = 0.001), and the recessive genetic model (OR = 1.44, 95% CI = 1.01 - 2.05, P_{heterogeneity} = 0.002) ; and in African descendants for homozygote comparison (OR = 2.59, 95% CI = 1.29 – 5.19, P_{heterogeneity} = 0.194) and the recessive genetic model (OR = 2.61, 95% CI = 1.30 – 5.23, P_{heterogeneity} = 0.195). In conclusion, the RNASEL Arg462Gln polymorphism may contribute to the risk of developing prostate cancer in African descendants and Hispanic Caucasians. Further larger and well-designed studies are warranted to evaluate this association in detail.

Influence of chronic inflammation on Bcl-2 and PCNA expression in prostate needle biopsy specimens

The association between inflammation and cancer has been established in certain forms of human malignancies; however, its role in prostate cancer remains unclear. The present study investigates a possible association between chronic inflammation and the development of epithelial neoplasia in the prostate. Needle biopsy specimens were obtained from patients with serum prostate-specific antigen levels >4 ng/ml, evaluated for morphological findings, and immunostained for Bcl-2 and proliferating cell nuclear antigen (PCNA). Bcl-2 is a survival protein that appears to lie at a nodal point in pathways involved in cell survival, carcinogenesis, and development of therapeutic resistance in certain cancer types. Similarly, PCNA is a critical protein for DNA replication, repair of DNA damage, chromatin structure maintenance, chromosome segregation and cell-cycle progression. The association between these two proteins was examined in prostate tissues with and without chronic inflammation, as well as tissues with and without evidence of neoplastic changes. Of the 106 needle biopsies examined, 18% exhibited atrophy with inflammation. Proliferative inflammatory atrophy/post-atrophic hyperplasia were observed in 42%, high-grade prostatic intraepithelial neoplasia (HGPIN) in 8%, prostatic adenocarcinoma in 11%, and 2% had atypical acinar proliferation suspicious for malignancy. A total of 36 specimens were stained for Bcl-2 and PCNA. Bcl-2 was expressed widely in inflammatory and epithelial tissue; however, more intense expression was observed in the areas of chronic inflammation, predominantly in infiltrating immune cells. The highest proliferation index was observed in the epithelia of HGPIN and cancer. An inverse correlation between the expression of Bcl-2 and the expression of PCNA was observed in the epithelium. The areas of chronic inflammation were associated with increased Bcl-2 expression, whereas the highly proliferative epithelium minimally expressed Bcl-2. These results suggest that Bcl-2 alters the phenotype of particular epithelial cells with a gain in neoplastic characteristics, leading to a likely precursor that may later progress into HGPIN and cancer.

Inflammation in Prostatic Hyperplasia and Carcinoma-Basic Scientific Approach

Chronic inflammation is associated with both benign conditions and cancer. Likewise, inflammatory cells are quite common in benign prostatic hyperplasia (BPH) and prostatic tissue harboring cancer. Triggers that activate inflammatory pathways in the prostate remain a subject of argument and are likely to be multifactorial, some of these being bacterial antigens, different chemical irritations, and metabolic disorders. Acute and chronic inflammation in prostate leads to accumulation of immunocompetent cells, mainly T lymphocytes and macrophages, but also neutrophils, eosinophils, and mast cells, depending on the type of offending agent. Inflammatory processes activate hyperproliferative programs resulting in nodules seen in BPH, but are also important in creating suitable microenvironment for cancer growth and progression. Inflammatory cells have mostly been shown to have a protumoral effect such as tumor-associated macrophages, but some cell types such as mast cells have antitumoral effects. This review outlines the recent findings and theories supporting the role of inflammatory responses as drivers of both benign and malignant epithelial processes in the prostate gland.

The Relationship between Obesity, Prostate Tumor Infiltrating Lymphocytes and Macrophages, and Biochemical Failure

BACKGROUND

Obesity reflects a chronic inflammatory environment that may contribute to prostate cancer progression and poor treatment outcomes. However, it is not clear which mechanisms drive this association within the tumor microenvironment. The aim of this pilot study was to examine prostatic inflammation via tumor infiltrating lymphocytes and macrophages characterized by obesity and cancer severity.

METHODS

We studied paraffin-embedded prostatectomy tissue from 99 participants (63 non-obese and 36 obese) from the Study of Clinical Outcomes, Risk and Ethnicity (University of Pennsylvania). Pathologists analyzed the tissue for type and count of lymphocytes and macrophages, including CD3, CD8, FOXP3, and CD68. Pathology data were linked to clinical and demographic variables. Statistical analyses included frequency tables, Kruskal-Wallis tests, Spearman correlations, and multivariable models.

RESULTS

We observed positive univariate associations between the number of CD68 cells and tumor grade (p = 0.019). In multivariable analysis, CD8 counts were associated with time to biochemical failure (HR = 1.09, 95% CI = 1.004-1.192, p-value = 0.041.) There were no differences in lymphocytes or macrophages by obesity status or BMI.

CONCLUSIONS

The number of lymphocytes and macrophages in the tumor microenvironment did not differ by obesity status. However, these inflammation markers were associated with poor prostate cancer outcomes. Further examination of underlying mechanisms that influence obesity-related effects on prostate cancer outcomes is warranted. Such research will guide immunotherapy protocols and weight management as they apply to diverse patient populations and phenotypes.

Racial differences in prostate inflammation: results from the REDUCE study

Prostate cancer (PC) risk differs between races, and we previously showed prostate inflammation in benign prostate tissue was linked with a lower future PC risk. However, whether prostate tissue inflammation varies by race is unknown. We analyzed baseline acute and chronic prostate inflammation by race in REDUCE, a 4-year, multicenter, placebo-controlled study where all men had a negative prostate biopsy prior to enrollment. We included 7,982 men with standardized central pathology review to determine the presence or absence of chronic or acute inflammation in baseline prostate biopsy tissue. Logistic regression was used to compare prostate inflammation by race, adjusting for confounders. Of 7,982 men, 7,271 were white (91.1%), 180 (2.3%) black, 131 (1.6%) Asian, 319 (4.0%) Hispanic and 81 (1%) unknown. A total of 78% had chronic and 15% had acute inflammation. On multivariable analysis relative to white men, black men were less likely (OR = 0.65, 95%CI: 0.41-1.03, p = 0.07) and Asian men more likely to have acute inflammation (OR = 1.74, 95%CI: 1.14-2.65, p = 0.001). Hispanic men had similar levels of acute inflammation as white men. Chronic inflammation did not significantly differ across races. We identified racial differences in acute inflammation, particularly in Asian men, in benign prostate tissue that inversely mirrored population-level data on PC race disparity. As we showed in REDUCE that acute inflammation is linked with lower future PC risk, if validated in future studies, these data suggest racial differences in prostatic acute inflammation may contribute in part to race differences in PC risk, especially among Asian men.

From Inflammation to Prostate Cancer: The Role of Inflammasomes

Inflammation-associated studies entice specific attention due to inflammation's role in multiple stages of prostate cancer development. However, mechanistic regulation of inflammation inciting prostate cancer remains largely uncharacterized. A focused class of inflammatory regulators known as inflammasomes has recently gained attention in cancer development. Inflammasomes are a multiprotein complex that drives a cascade of proinflammatory cytokines regulating various cellular activities. Inflammasomes activation is linked with infection, stress, or danger signals, which are common events within the prostate gland. In this study, we review the potential of inflammasomes in understanding the role of inflammation in prostate cancer.

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.

Immune Infiltration and Prostate Cancer

It is becoming increasingly clear that inflammation influences prostate cancer (PCa) development and that immune cells are among the primary drivers of this effect. This information has launched numerous clinical trials testing immunotherapy drugs in PCa patients. The results of these studies are promising but have yet to generate a complete response. Importantly, the precise immune profile that determines clinical outcome remains unresolved. Individual immune cell types are divided into various functional subsets whose effects on tumor development may differ depending on their particular phenotype and functional status, which is often shaped by the tumor microenvironment. Thus, this review aims to examine the current knowledge regarding the role of inflammation and specific immune cell types in mediating PCa progression to assist in directing and optimizing immunotherapy targets, regimens, and responses and to uncover areas in which further research is needed. Finally, a summary of ongoing immunotherapy clinical trials in PCa is provided.

Histopathologic characterization of prostate diseases in Madinah, Saudi Arabia

AIMS

To delineate the histopathological pattern of prostate diseases and to highlight age variations in prostate specific antigen (PSA) values and histopathological features.

MATERIALS AND METHODS

A retrospective review was made of all prostate biopsy reports seen between January 2006 and December 2013 at the King Fahad Hospital, Madinah, Saudi Arabia. Prostate lesions were tabulated and classified into benign and malignant groups. Histological scoring of adenocarcinomas was accomplished using the Gleason system. PSA values were correlated with Gleason scores.

RESULTS

Of 417 prostate lesions reviewed, 343 (82.3%) were benign and 74 (17.7%) were malignant, giving a benign to malignant ratio of 4.6:1. Benign prostatic hyperplasia (both with and without inflammation) was the commonest prostatic lesion and accounted for 80.3% of all cases and 97.6% of all benign cases. The age range was 20 to 97 years with a mean of 69.2 years and a peak age group at 70-79 years. Seventy one cases of adenocarcinoma accounted for 95.9% of the total of 74 malignant tumors. It showed an age range of 44 to 95 years, a mean age of 70.9 years and peak prevalence in the 80-89 year age group. Gleason score seven was the most frequent (39.4%) in occurrence. Most adenocarcinomas, 41 cases (57.7%), were moderately differentiated (Gleason score of 5-7). PSA values ranged widely between 16-1,865 ng/ml with a mean of 363.4 ng/ml. Elevated PSA (>100 ng/ml) levels were found in 53 (81.6%) patients. There was a statistically significant positive correlation between serum PSA level and Gleason score (p=0.0304).

CONCLUSIONS

Prostatic lesions constitute a significant source of morbidity among adult males in Madinah. Benign prostatic hyperplasia was the commonest benign prostatic lesion and adenocarcinoma was the commonest histological subtype of prostatic cancer.

The host microenvironment influences prostate cancer invasion, systemic spread, bone colonization, and osteoblastic metastasis

Prostate cancer (PCa) is the second leading cause of cancer death in men worldwide. Most PCa deaths are due to osteoblastic bone metastases. What triggers PCa metastasis to the bone and what causes osteoblastic lesions remain unanswered. A major contributor to PCa metastasis is the host microenvironment. Here, we address how the primary tumor microenvironment influences PCa metastasis via integrins, extracellular proteases, and transient epithelia-mesenchymal transition (EMT) to promote PCa progression, invasion, and metastasis. We discuss how the bone-microenvironment influences metastasis; where chemotactic cytokines favor bone homing, adhesion molecules promote colonization, and bone-derived signals induce osteoblastic lesions. Animal models that fully recapitulate human PCa progression from primary tumor to bone metastasis are needed to understand the PCa pathophysiology that leads to bone metastasis. Better delineation of the specific processes involved in PCa bone metastasize is needed to prevent or treat metastatic PCa. Therapeutic regimens that focus on the tumor microenvironment could add to the PCa pharmacopeia.

Incidental prostate ¹⁸F-FDG uptake without calcification indicates the possibility of prostate cancer

Incidental ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake in the prostate is often experienced in clinical practice; however, it is difficult to determine whether incidental uptake is indicative of a malignancy or benign state based on the maximum standardized uptake value (SUVmax). In the present study, we investigated the clinical significance of incidental prostate uptake by ¹⁸F-FDG positron emission tomography (PET)/CT, and examined the differences between malignant and benign uptake from a clinicopathological viewpoint. We reviewed 3,236 male subjects who underwent ¹⁸F-FDG PET/CT scans at Hirosaki University Hospital (Japan) from 2008 to 2012 in order to identify cases of incidental prostate FDG uptake. The final diagnosis was made by serum prostate-specific antigen (PSA) levels, biopsy, imaging studies and clinical follow-up with PET findings. Incidental FDG uptake of the prostate was observed in 53 cases (2%). Four cases were excluded due to insufficient clinical data, and 49 cases were included in the present study. Of the 49 cases, 8 (16%) had prostate cancer, while 41 (84%) were benign. All 8 malignant cases had high uptake areas, e.g. in the prostate peripheral zone, where there was no coexistence of calcification or FDG uptake. Of the 41 benign cases, 19 had high uptake in the inner zone, 17 in the peripheral zone, and 5 in both the inner and peripheral zones. Of the 41 cases, 18 (44%) showed FDG uptake coexisting with prostatic calcification. Incidental prostate ¹⁸F-FDG uptake infrequently signifies prostate cancer; however, FDG uptake not coexisting with calcification indicates the possibility of prostate cancer and should be included in the differential diagnosis for performing other clinical examinations.

Exposure of Prostate to Lipopolysaccharide and Hypoxia Potentiates Neoplastic Behavior and Risk for Prostate Carcinogenesis In Vivo

A number of studies showed that men from tropical countries have higher burden of prostate cancer similar to data from USA. We developed a translational model to examine whether exposure to microbial inflammation-inducing molecule lipopolysacchride LPS was associated with prostatic cell transformation to more proliferative phenotype as indicated by PSA secretion. Immunocompetent adult mice were divided into two groups; the first group received a local prostate inoculation with E. coli, while the second group received inoculation with sterile solution of saline as vehicle. At the end of 6 days, the PSA values were measured and compared. In the second experiment, two groups of animals were involved. The test group received two drops of the hydrogen peroxide orally for six to seven days to induce hypoxia, while the control group received normal saline. Blood samples were evaluated for serum level of PSA. Result showed a 2-fold increase in level of PSA compared to the control mice in the E. coli inoculated-LPS exposed animals. In addition, exposure of the animals to hypoxic stress resulted in 3.5 fold increase in the serum PSA compared to the control group, which was found to be statistically significant (P < 0.0001). In conclusion, our data shows that chronic prostatic infection and exposure to inflammatory stimulus, especially LPS, may alter the phenotype of prostate epithelial cells for increased PSA secretion, a known cancer-like behavior; this is mediated by compromised redox state and oxidative stress injury. We propose that exposure of the prostate epithelial cells to lipopolysaccharide (LPS) promotes chronic inflammation and risk of neoplastic behavior of the prostate in vivo; this may explain the high rate of prostate cancer in tropics.