Assessment of aberrations on chromosome 8 in prostatic atrophy

Comprehensive Genomic Profiling of Androgen-Receptor-Negative Canine Prostate Cancer

Canine carcinomas have been considered natural models for human diseases; however, the genomic profile of canine prostate cancers (PCs) has not been explored. In this study, 14 PC androgen-receptor-negative cases, 4 proliferative inflammatory atrophies (PIA), and 5 normal prostate tissues were investigated by array-based comparative genomic hybridization (aCGH). Copy number alterations (CNAs) were assessed using the Canine Genome CGH Microarray 4 × 44K (Agilent Technologies). Genes covered by recurrent CNAs were submitted to enrichment and cross-validation analysis. In addition, the expression levels of TP53, MDM2 and ZBTB4 were evaluated in an independent set of cases by qPCR. PC cases presented genomic complexity, while PIA samples had a small number of CNAs. Recurrent losses covering well-known tumor suppressor genes, such as ATM, BRCA1, CDH1, MEN1 and TP53, were found in PC. The in silico functional analysis showed several cancer-related genes associated with canonical pathways and interaction networks previously described in human PC. The MDM2, TP53, and ZBTB4 copy number alterations were translated into altered expression levels. A cross-validation analysis using The Cancer Genome Atlas (TCGA) database for human PC uncovered similarities between canine and human PCs. Androgen-receptor-negative canine PC is a complex disease characterized by high genomic instability, showing a set of genes with similar alterations to human cancer.

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.

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.

Periacinar retraction clefting in proliferative prostatic atrophy and prostatic adenocarcinoma

AIMS

To evaluate the presence and extent of periacinar retraction clefting in proliferative prostatic atrophy and carcinoma in radical prostatectomy specimens.

METHODS

Atrophic foci and neoplastic glands were analysed in specimens from 50 patients who underwent radical prostatectomy. Analysed atrophic glands were classified in two main groups, proliferative atrophy (PA) and proliferative inflammatory atrophy (PIA); each group was subclassified into simple atrophy (SA) and postatrophic hyperplasia (PAH). According to the presence and extent of periacinar retraction clefting, atrophic and neoplastic glands were classified as: group 1, glands without clefts or with clefts affecting 50% of the circumference in <50% of examined glands; and group 3, glands with clefts that affected >50% of the circumference in >or=50% of examined glands.

RESULTS

Forty-four (88.0%) atrophic foci were without periacinar clefts or clefts were present in less than half of the gland circumference (group 1). In 6 (12.0%), atrophic foci clefts affected >50% of gland circumference (groups 2 and 3). Forty-five (90.0%) carcinomas were with clefts which affected more than 50% of gland circumference (groups 2 and 3); and in five carcinomas only, clefts were not found or affected <50% of gland circumference (group 1).

CONCLUSION

Results indicate that periacinar retraction clefting represents a reliable criterion in differential diagnosis between proliferative atrophy and carcinoma.

Inflammation and chronic prostatic diseases: evidence for a link?

OBJECTIVES

Emerging evidence indicates that prostatic inflammation may contribute to prostate growth either in terms of hyperplastic (benign prostatic hyperplasia [BPH]) or neoplastic (prostate cancer [PCa]) changes. We propose two questions: Does prostate inflammation represent a significant factor for the development and the progression of both BPH and PCa? Are data available now to sustain the identification of prostate inflammation as a risk factor for prostate diseases?

METHODS

We reviewed the recent international literature using a PubMed search to analyze new findings supporting a role for inflammation in BPH and PCa growth and progression.

RESULTS

On histologic examinations from patients with BPH, inflammatory aspects are present in approximately 40% of cases. The men with inflammatory aspects inside the prostate have a significantly higher risk for BPH progression and acute urinary retention. Evidence shows that a cyclooxygenase-2 (COX-2) inhibitor can increase the apoptotic activity in human BPH tissue. Analyses on the bacterial colonization in PCa and normal prostate tissue showed a highly suggestive correlation between bacterial colonization/chronic inflammation and the diagnosis of PCa. Evidence from genetic studies supports the hypothesis that prostate inflammation may be a cause of PCa development. Proliferative inflammatory atrophy has been considered as an early histologic precursor to prostatic intraepithelial neoplasia and PCa.

CONCLUSION

The concept that inflammation can promote chronic prostatic diseases, such as BPH or PCa, is actually supported by several new significant findings; however, no specific oncologic surveillance for these cases is justified at the moment.

Two common chromosome 8q24 variants are associated with increased risk for prostate cancer

Two variants (rs1447295/DG8S737) of chromosome 8q24 were recently reported to be associated with increased risk of prostate cancer (PC). To confirm this finding, we genotyped and compared the frequencies of these polymorphisms among 1,121 Caucasian men with PC (435 men with familial PC, 491 men with sporadic PC, and 195 men with aggressive PC) to 545 population-based controls. For the single nucleotide polymorphism marker rs1447295, frequencies of the minor allele (A) were 10.3% in controls, 11.9% in sporadic cases, 16.7% in familial cases, and 17.2% in aggressive cases. Compared with controls, the A allele was significantly more common in both familial PC [odds ratios (OR), 1.93; 95% confidence intervals (95% CI), 1.37-2.72; P = 0.0004] and aggressive PC (OR, 1.87; 95% CI, 1.28-2.74; P = 0.0005) but not for sporadic PC (OR, 1.16; 95% CI, 0.85-1.58; P = 0.25). Although the A allele was more frequent in aggressive PC cases when compared with controls, the allele frequencies were similar among cases with high- and low-grade PC (Gleason grades <7 and >/=7, respectively). For the microsatellite marker DG8S737, the -8 allele was significantly more frequent in familial PC (OR, 1.68; 95% CI, 1.09-2.60; P = 0.031), whereas the -10 allele was more frequent in aggressive PC (OR, 2.85; 95% CI, 1.52-5.36; P = 0.0004). Haplotype analysis showed significant differences in haplotype frequencies between the familial PC (P = 0.006) and aggressive PC (P = 0.005) cases versus controls. The -8/A haplotype showed the strongest association with familial PC (P = 0.008), whereas the -10/A haplotype was most strongly associated with aggressive PC (P = 0.00005). These results further confirm the importance of these two polymorphic variants (rs1447295 and DG8S737) as risk factors for PC. However, the mechanism explaining this increased risk has not yet been established.

Inflammation in prostate carcinogenesis

About 20% of all human cancers are caused by chronic infection or chronic inflammatory states. Recently, a new hypothesis has been proposed for prostate carcinogenesis. It proposes that exposure to environmental factors such as infectious agents and dietary carcinogens, and hormonal imbalances lead to injury of the prostate and to the development of chronic inflammation and regenerative 'risk factor' lesions, referred to as proliferative inflammatory atrophy (PIA). By developing new experimental animal models coupled with classical epidemiological studies, genetic epidemiological studies and molecular pathological approaches, we should be able to determine whether prostate cancer is driven by inflammation, and if so, to develop new strategies to prevent the disease.

Gain of chromosome X in prostatic atrophy detected by CGH and FISH analyses

BACKGROUND

Focal atrophy is presumed to be an indirect forerunner of prostate cancer. The aim of this study was to examine genetic alterations in prostate epithelia deriving from atrophic areas and compare these findings with those of cells deriving from paired prostate cancer in the same patient.

METHODS

Formalin fixed paraffin wax-embedded prostatectomy specimens from 20 prostate cancer patients were utilized in this study. Comparative Genomic Hybridization (CGH) was performed on atrophic areas. To validate the CGH results, Fluorescence in Situ Hybridization (FISH) analysis was performed on atrophic areas and paired cancer tissue.

RESULTS

Gain of the whole chromosome X was found as sole aberration in seven (70%) atrophic tissues by CGH. A gain of centromere X was observed in 13 (68.4%) atrophic areas and in 18 (90%) cancer tissues using FISH.

CONCLUSIONS

Our investigation reconfirms the genetical instability of cells of the atrophic acini and attention of relevance of gain of chromosome X in atrophic areas.