Proliferative Inflammatory Atrophy of the Prostate
1999; Elsevier BV; Volume: 155; Issue: 6 Linguagem: Inglês
10.1016/s0002-9440(10)65517-4
ISSN1525-2191
AutoresAngelo M. De Marzo, Valérie Marchi, Jonathan I. Epstein, William G. Nelson,
Tópico(s)Prostate Cancer Treatment and Research
ResumoProliferation in the setting of longstanding chronic inflammation appears to predispose to carcinoma in the liver, large bowel, urinary bladder, and gastric mucosa. Focal prostatic atrophy, which is associated with chronic inflammation, is highly proliferative (Ruska et al, Am J Surg Pathol 1998, 22:1073–1077); thus the focus of this study was to more fully characterize the phenotype of the atrophic cells to assess the feasibility of the proposal that they may be targets of neoplastic transformation. The π-class glutathione S-transferase (GSTP1), a carcinogen-detoxifying enzyme, is not expressed in >90% of prostate carcinomas (CaPs). GSTP1 promoter hypermethylation, which appears to permanently silence transcription, is the most frequently detected genomic alteration in CaP (Lee et al, Proc Natl Acad Sci USA 1994, 91:11733–11737; >90% of cases). In high-grade prostatic intraepithelial neoplasia (PIN), this alteration is present in at least 70% of cases (Brooks et al, Cancer Epidemiol Biomarkers Prev, 1998, 7:531–536). Although normal-appearing prostate secretory cells rarely express GSTP1, they remain capable of expression, inasmuch as GSTP1 promoter hypermethylation is not detected in normal prostate. Fifty-five lesions from paraffin-embedded prostatectomy specimens (n = 42) were stained for GSTP1, using immunohistochemistry. Adjacent sections were stained for p27Kip1, Ki-67, androgen receptor (AR), prostate-specific antigen (PSA), prostate-specific acid phosphatase (PSAP), Bcl-2, and basal cell-specific cytokeratins (34βE12). With normal prostate epithelium as the internal standard, staining was scored for each marker in the atrophic epithelium. The lesions showed two cell types, basal cells staining positive for 34βE12, and atrophic secretory-type cells staining weakly negative for 34βE12. All lesions showed elevated levels of Bcl-2 in many of the secretory-type cells. All lesions had an elevated staining index for the proliferation marker Ki-67 in the secretory layer and decreased expression of p27Kip1, a finding reminiscent of high-grade PIN (De Marzo et al, Am J Pathol 1998, 153:911–919). Consistent with partial secretory cell differentiation, the luminal cells showed weak to moderate staining for androgen receptor and the secretory proteins PSA and PSAP. All atrophic lesions showed elevated GSTP1 expression in many of the luminal secretory-type cells. Because all lesions are hyperproliferative, are associated with inflammation, and have the distinct morphological appearance recognized as prostatic atrophy, we suggest the term "proliferative inflammatory atrophy" (PIA). Elevated levels of GSTP1 may reflect its inducible nature in secretory cells, possibly in response to increased electrophile or oxidant stress. Elevated Bcl-2 expression may be responsible for the very low apoptotic rate in PIA and is consistent with the conclusion that PIA is a regenerative lesion. We discuss our proposal to integrate the atrophy and high-grade PIN hypotheses of prostate carcinogenesis by suggesting that atrophy may give rise to carcinoma either directly, as previously postulated, or indirectly by first developing into high-grade PIN. Proliferation in the setting of longstanding chronic inflammation appears to predispose to carcinoma in the liver, large bowel, urinary bladder, and gastric mucosa. Focal prostatic atrophy, which is associated with chronic inflammation, is highly proliferative (Ruska et al, Am J Surg Pathol 1998, 22:1073–1077); thus the focus of this study was to more fully characterize the phenotype of the atrophic cells to assess the feasibility of the proposal that they may be targets of neoplastic transformation. The π-class glutathione S-transferase (GSTP1), a carcinogen-detoxifying enzyme, is not expressed in >90% of prostate carcinomas (CaPs). GSTP1 promoter hypermethylation, which appears to permanently silence transcription, is the most frequently detected genomic alteration in CaP (Lee et al, Proc Natl Acad Sci USA 1994, 91:11733–11737; >90% of cases). In high-grade prostatic intraepithelial neoplasia (PIN), this alteration is present in at least 70% of cases (Brooks et al, Cancer Epidemiol Biomarkers Prev, 1998, 7:531–536). Although normal-appearing prostate secretory cells rarely express GSTP1, they remain capable of expression, inasmuch as GSTP1 promoter hypermethylation is not detected in normal prostate. Fifty-five lesions from paraffin-embedded prostatectomy specimens (n = 42) were stained for GSTP1, using immunohistochemistry. Adjacent sections were stained for p27Kip1, Ki-67, androgen receptor (AR), prostate-specific antigen (PSA), prostate-specific acid phosphatase (PSAP), Bcl-2, and basal cell-specific cytokeratins (34βE12). With normal prostate epithelium as the internal standard, staining was scored for each marker in the atrophic epithelium. The lesions showed two cell types, basal cells staining positive for 34βE12, and atrophic secretory-type cells staining weakly negative for 34βE12. All lesions showed elevated levels of Bcl-2 in many of the secretory-type cells. All lesions had an elevated staining index for the proliferation marker Ki-67 in the secretory layer and decreased expression of p27Kip1, a finding reminiscent of high-grade PIN (De Marzo et al, Am J Pathol 1998, 153:911–919). Consistent with partial secretory cell differentiation, the luminal cells showed weak to moderate staining for androgen receptor and the secretory proteins PSA and PSAP. All atrophic lesions showed elevated GSTP1 expression in many of the luminal secretory-type cells. Because all lesions are hyperproliferative, are associated with inflammation, and have the distinct morphological appearance recognized as prostatic atrophy, we suggest the term "proliferative inflammatory atrophy" (PIA). Elevated levels of GSTP1 may reflect its inducible nature in secretory cells, possibly in response to increased electrophile or oxidant stress. Elevated Bcl-2 expression may be responsible for the very low apoptotic rate in PIA and is consistent with the conclusion that PIA is a regenerative lesion. We discuss our proposal to integrate the atrophy and high-grade PIN hypotheses of prostate carcinogenesis by suggesting that atrophy may give rise to carcinoma either directly, as previously postulated, or indirectly by first developing into high-grade PIN. Chronic inflammation of longstanding duration has been linked to the development of carcinoma in several organ systems.1Ames BN Mutagenesis and carcinogenesis: endogenous and exogenous factors.Environ Mol Mutagen. 1989; 14: 66-77Crossref PubMed Scopus (222) Google Scholar, 2Weitzman SA Gordon LI Inflammation and cancer: role of phagocyte-generated oxidants in carcinogenesis.Blood. 1990; 76: 655-663Crossref PubMed Google Scholar, 3Bartsch H Frank N Blocking the endogenous formation of N-nitroso compounds and related carcinogens.IARC Sci Publ. 1996; 139: 189-201PubMed Google Scholar The proposed mechanism of carcinogenesis involves repeated tissue damage and regeneration in the presence of highly reactive oxygen and nitrogen species. These reactive molecules, such as H202 and nitric oxide (NO), are released from the inflammatory cells and can interact with DNA in the proliferating epithelium to produce permanent genomic alterations such as point mutations, deletions, and rearrangements.2Weitzman SA Gordon LI Inflammation and cancer: role of phagocyte-generated oxidants in carcinogenesis.Blood. 1990; 76: 655-663Crossref PubMed Google Scholar, 3Bartsch H Frank N Blocking the endogenous formation of N-nitroso compounds and related carcinogens.IARC Sci Publ. 1996; 139: 189-201PubMed Google Scholar This inflammation-carcinoma sequence as been invoked as a potential mechanism with regard to prostatic carcinogenesis.4Smith CJ Gardner Jr, WA Inflammation-proliferation: possible relationships in the prostate.Prog Clin Biol Res. 1987; 239: 317-325PubMed Google Scholar, 5Bennett BD Richardson PH Gardner WA Histopathology and cytology of prostatitis.in: Lepor H Lawson RK Prostate Diseases. W. B. Saunders Company, Philadelphia1993: 399-414Google Scholar, 6Bennett BD Culberson DE Petty CS Gardner WA Histopathology of prostatitis.J Urol. 1990; 143: 265AGoogle Scholar, 7Gardner WA Bennett BD The prostate-overview: recent insights and speculations.in: Weinstein RS Gardner WA Pathology and Pathobiology of the Urinary Bladder and Prostate. Williams and Wilkins, Baltimore1992: 129-148Google Scholar, 8Platz EA Prostatitis and prostate cancer.New Dev Prostate Cancer Treatment. 1998; 3: 71-73Google Scholar, 9De Marzo AM Coffey DS Nelson WG New concepts in tissue specificity for prostate cancer and benign prostatic hyperplasia.Urology. 1999; 53: 29-39Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar Interestingly, focal prostatic glandular atrophy, which has been put forth previously as a potential precursor of prostatic adenocarcinoma,10Franks LM Atrophy and hyperplasia in the prostate proper.J Pathol Bacteriol. 1954; 68: 617-621Crossref PubMed Scopus (149) Google Scholar, 11Liavag I Atrophy and regeneration in the pathogenesis of prostatic carcinoma.Acta Pathol Microbiol Scand. 1968; 73: 338-350Crossref PubMed Scopus (72) Google Scholar occurs in close association with chronic inflammation.5Bennett BD Richardson PH Gardner WA Histopathology and cytology of prostatitis.in: Lepor H Lawson RK Prostate Diseases. W. B. Saunders Company, Philadelphia1993: 399-414Google Scholar, 12McNeal JE Normal histology of the prostate.Am J Surg Pathol. 1988; 12: 619-633Crossref PubMed Scopus (461) Google Scholar, 13McNeal JE Prostate.in: Sternberg SS Histology for Pathologists. ed 2. Lippincott-Raven, Philadelphia1997: 997-1017Google Scholar Atrophy of the prostate is identified as a reduction in the volume of preexisting glands and stroma and can be divided into two major patterns, diffuse and focal.12McNeal JE Normal histology of the prostate.Am J Surg Pathol. 1988; 12: 619-633Crossref PubMed Scopus (461) Google Scholar, 14McNeal JE Aging and the prostate.in: Brocklehurst JC Urology in the Elderly. Churchill Livingstone, Edinburgh1984: 193-202Google Scholar Diffuse atrophy results from a decrease in circulating androgens and involves the entire prostate in a relatively uniform manner.15McNeal JE Regional morphology and pathology of the prostate.Am J Clin Pathol. 1968; 49: 347-357PubMed Google Scholar In contrast, focal atrophy is not related to decreased circulating androgens, and it occurs as patches of atrophic epithelium within a background of surrounding normal-appearing nonatrophic epithelium.12McNeal JE Normal histology of the prostate.Am J Surg Pathol. 1988; 12: 619-633Crossref PubMed Scopus (461) Google Scholar Franks10Franks LM Atrophy and hyperplasia in the prostate proper.J Pathol Bacteriol. 1954; 68: 617-621Crossref PubMed Scopus (149) Google Scholar indicated that focal prostatic atrophy lesions occur chiefly in the "outer" portion of the prostate (referred to by McNeal as the "peripheral zone")12McNeal JE Normal histology of the prostate.Am J Surg Pathol. 1988; 12: 619-633Crossref PubMed Scopus (461) Google Scholar and that they increase in frequency with advancing age. Others confirmed these findings.11Liavag I Atrophy and regeneration in the pathogenesis of prostatic carcinoma.Acta Pathol Microbiol Scand. 1968; 73: 338-350Crossref PubMed Scopus (72) Google Scholar, 13McNeal JE Prostate.in: Sternberg SS Histology for Pathologists. ed 2. Lippincott-Raven, Philadelphia1997: 997-1017Google Scholar, 16Gardner Jr, WA Culberson DE Atrophy and proliferation in the young adult prostate.J Urol. 1987; 137: 53-56PubMed Google Scholar, 17Billis A Prostatic atrophy: an autopsy study of a histologic mimic of adenocarcinoma.Mod Pathol. 1998; 11: 47-54PubMed Google Scholar How might atrophic cells be linked to carcinoma, which also occurs principally in the peripheral zone? While most focal prostatic atrophy lesions have been considered to be quiescent,13McNeal JE Prostate.in: Sternberg SS Histology for Pathologists. ed 2. Lippincott-Raven, Philadelphia1997: 997-1017Google Scholar cells in some atrophy lesions appear proliferative.10Franks LM Atrophy and hyperplasia in the prostate proper.J Pathol Bacteriol. 1954; 68: 617-621Crossref PubMed Scopus (149) Google Scholar, 11Liavag I Atrophy and regeneration in the pathogenesis of prostatic carcinoma.Acta Pathol Microbiol Scand. 1968; 73: 338-350Crossref PubMed Scopus (72) Google Scholar, 18Liavag I Mitotic activity of prostatic epithelium. A study by means of Colcemid.Acta Pathol Microbiol Scand. 1968; 73: 19-28Crossref PubMed Scopus (10) Google Scholar, 19Stiens R Helpap B Bruhl P The proliferation of prostatic epithelium in chronic prostatitis.Urol Res. 1975; 3: 21-24Crossref PubMed Scopus (4) Google Scholar In a comparison between benign nonatrophic epithelium and focal prostatic atrophy, Ruska et al recently demonstrated that, while there was no increase in the apoptotic index, atrophy exhibited a markedly increased immunohistochemical staining index for the proliferation marker, Ki-67.20Ruska KM Sauvageot J Epstein JI Histology and cellular kinetics of prostatic atrophy.Am J Surg Pathol. 1998; 22: 1073-1077Crossref PubMed Scopus (118) Google Scholar This finding supports the contention that focal atrophy represents either a de novo proliferative lesion or a regenerative lesion resulting from replacement of cellular loss, as suggested previously.11Liavag I Atrophy and regeneration in the pathogenesis of prostatic carcinoma.Acta Pathol Microbiol Scand. 1968; 73: 338-350Crossref PubMed Scopus (72) Google Scholar Most cell division in the normal human prostate epithelium occurs in the basal cell compartment.21Bonkhoff H Stein U Remberger K The proliferative function of basal cells in the normal and hyperplastic human prostate.Prostate. 1994; 24: 114-118Crossref PubMed Scopus (220) Google Scholar, 22McNeal JE Haillot O Yemoto C Cell proliferation in dysplasia of the prostate: analysis by PCNA immunostaining.Prostate. 1995; 27: 258-268Crossref PubMed Scopus (51) Google Scholar Yet high-grade PIN, the presumed precursor of many prostatic adenocarcinomas,23Bostwick DG Prospective origins of prostate carcinoma. Prostatic intraepithelial neoplasia and atypical adenomatous hyperplasia.Cancer. 1996; 78: 330-336Crossref PubMed Scopus (141) Google Scholar and adenocarcinoma cells possess phenotypic and morphological features of secretory cells. Thus cell proliferation has been shifted up from the basal into the secretory compartment in high-grade PIN and in carcinoma.21Bonkhoff H Stein U Remberger K The proliferative function of basal cells in the normal and hyperplastic human prostate.Prostate. 1994; 24: 114-118Crossref PubMed Scopus (220) Google Scholar, 22McNeal JE Haillot O Yemoto C Cell proliferation in dysplasia of the prostate: analysis by PCNA immunostaining.Prostate. 1995; 27: 258-268Crossref PubMed Scopus (51) Google Scholar Based on this "topographic infidelity of proliferation" (TIP),24De Marzo AM Nelson WG Meeker AM Coffey DS Stem cell features of benign and malignant prostate epithelial cells.J Urol. 1998; 160: 2381-2392Abstract Full Text Full Text PDF PubMed Scopus (186) Google Scholar as well as patterns of cytokeratin expression,25Verhagen AP Ramaekers FC Aalders TW Schaafsma HE Debruyne FM Schalken JA Colocalization of basal and luminal cell-type cytokeratins in human prostate cancer.Cancer Res. 1992; 52: 6182-6187PubMed Google Scholar it has been postulated that the prostatic cell type that is the target of neoplastic transformation is an intermediate cell, with some features of basal cells and some of secretory cells. No prior studies have specifically examined the immunophenotype of the cells within focal atrophy of the prostate. To better elucidate the cell types present and to further explore the possibility that cells in focal atrophy of the prostate may be related to carcinoma and high-grade PIN, we performed a detailed morphological and immunohistochemical analysis. We examined expression of both basal cell-specific and secretory cell-specific markers. In addition, we examined the expression patterns of other molecular markers implicated in prostatic carcinogenesis: p27Kip1, Bcl-2, and the π-class glutathione S-transferase (GSTP1). p27Kip1 is a cyclin-dependent kinase inhibitor whose expression is reduced in the majority of prostatic adenocarcinomas26De Marzo A Meeker A Epstein J Coffey D Prostate stem cell compartments: expression of p27Kip1 in normal, hyperplastic and cancer cells.Am J Pathol. 1998; 153: 911-919Abstract Full Text Full Text PDF PubMed Scopus (195) Google Scholar, 27Yang RM Naitoh J Murphy M Wang HJ Phillipson J deKernion JB Loda M Reiter RE Low p27 expression predicts poor disease-free survival in patients with prostate cancer.J Urol. 1998; 159: 941-945Abstract Full Text Full Text PDF PubMed Scopus (277) Google Scholar, 28Cheville JC Lloyd RV Sebo TJ Cheng L Erickson L Bostwick DG Lohse CM Wollan P Expression of p27kip1 in prostatic adenocarcinoma.Mod Pathol. 1998; 11: 324-328PubMed Google Scholar, 29Tsihlias J Kapusta LR DeBoer G Morava-Protzner I Zbieranowski I Bhattacharya N Catzavelos GC Klotz LH Slingerland JM Loss of cyclin-dependent kinase inhibitor p27Kip1 is a novel prognostic factor in localized human prostate adenocarcinoma.Cancer Res. 1998; 58: 542-548PubMed Google Scholar, 30Guo YP Sklar GN Borkowski A Kyprianou N Loss of the cyclin-dependent kinase inhibitor P27(Kip1) protein in human prostate cancer correlates with tumor grade.Clin Cancer Res. 1997; 3: 2269-2274PubMed Google Scholar, 31Cote RJ Shi Y Groshen S Feng AC Cordon-Cardo C Skinner D Lieskovosky G Association of p27Kip1 levels with recurrence and survival in patients with stage C prostate carcinoma.J Natl Cancer Inst. 1998; 90: 916-920Crossref PubMed Scopus (189) Google Scholar, 32Cordon-Cardo C Koff A Drobnjak M Capodieci P Osman I Millard SS Gaudin PB Fazzari M Zhang ZF Massague J Scher HI Distinct altered patterns of p27KIP1 gene expression in benign prostatic hyperplasia and prostatic carcinoma.J Natl Cancer Inst. 1998; 90: 1284-1291Crossref PubMed Scopus (247) Google Scholar and in high-grade PIN.26De Marzo A Meeker A Epstein J Coffey D Prostate stem cell compartments: expression of p27Kip1 in normal, hyperplastic and cancer cells.Am J Pathol. 1998; 153: 911-919Abstract Full Text Full Text PDF PubMed Scopus (195) Google Scholar GSTP1, which functions as an inducible phase II detoxifying enzyme for reactive oxygen species and organic electrophiles,33Coles B Ketterer B The role of glutathione and glutathione transferases in chemical carcinogenesis.Crit Rev Biochem Mol Biol. 1990; 25: 47-70Crossref PubMed Scopus (449) Google Scholar, 34Rushmore TH Pickett CB Glutathione S-transferases, structure, regulation, and therapeutic implications.J Biol Chem. 1993; 268: 11475-11478Abstract Full Text PDF PubMed Google Scholar is inactivated by promoter hypermethylation in human prostatic carcinoma.35Lee WH Morton RA Epstein JI Brooks JD Campbell PA Bova GS Hsieh WS Isaacs WB Nelson WG Cytidine methylation of regulatory sequences near the pi-class glutathione S-transferase gene accompanies human prostatic carcinogenesis.Proc Natl Acad Sci USA. 1994; 91: 11733-11737Crossref PubMed Scopus (756) Google Scholar, 36Lee WH Isaacs WB Bova GS Nelson WG CG island methylation changes near the GSTP1 gene in prostatic carcinoma cells detected using the polymerase chain reaction: a new prostate cancer biomarker.Cancer Epidemiol Biomarkers Prev. 1997; 6: 443-450PubMed Google Scholar, 37Brooks JD Weinstein M Lin X Sun Y Pin SS Bova GS Epstein JI Isaacs WB Nelson WG CG island methylation changes near the GSTP1 gene in prostatic intraepithelial neoplasia.Cancer Epidemiol Biomarkers Prev. 1998; 7: 531-536PubMed Google Scholar Expression of GSTP1 is also absent in high-grade PIN,37Brooks JD Weinstein M Lin X Sun Y Pin SS Bova GS Epstein JI Isaacs WB Nelson WG CG island methylation changes near the GSTP1 gene in prostatic intraepithelial neoplasia.Cancer Epidemiol Biomarkers Prev. 1998; 7: 531-536PubMed Google Scholar with promoter hypermethylation occurring in at least 70% of cases.37Brooks JD Weinstein M Lin X Sun Y Pin SS Bova GS Epstein JI Isaacs WB Nelson WG CG island methylation changes near the GSTP1 gene in prostatic intraepithelial neoplasia.Cancer Epidemiol Biomarkers Prev. 1998; 7: 531-536PubMed Google Scholar In this study, we report a down-regulation of p27Kip1 in prostatic atrophy, consistent with its proposed role as a suppressor of prostatic epithelial cell proliferation. We also report increased expression of Bcl-2, which is consistent with the observed very low levels of apoptosis.20Ruska KM Sauvageot J Epstein JI Histology and cellular kinetics of prostatic atrophy.Am J Surg Pathol. 1998; 22: 1073-1077Crossref PubMed Scopus (118) Google Scholar Finally, there was a striking increase in the expression of GSTP1 in many of the atrophic cells, indicative of a stress-induced response. Potential mechanisms of formation of prostatic atrophy are discussed, as well as the implications for prostatic carcinogenesis. The anti-androgen receptor antibody was obtained and used as undiluted mouse monoclonal antibody hybridoma supernatant from clone AR-441 (a gift from Dean P. Edwards, Ph.D., University of Colorado HSC, Denver, CO). Antibodies against prostate-specific antigen (PSA) (mouse monoclonal, clone ER-PR8, dilution 1:50), prostate-specific acid phosphatase (PSAP) (rabbit polyclonal, dilution 1:10,000), Bcl-2 (mouse monoclonal, dilution 1:25), CD20 (mouse monoclonal, clone L26, dilution 1:200), CD3 (mouse monoclonal, clone UCHT1, dilution 1:150), and CD68 (mouse monoclonal, clone KP-1, dilution 1:4000) were from Dako (Carpinteria, CA). Anti-p27Kip1 (mouse monoclonal, dilution 1:800) and anti-PCNA (mouse monoclonal, dilution 1:250) were from Transduction Laboratories (Lexington, KY). Anti-Ki-67 (mouse monoclonal, clone Mib-1, dilution 1:100) was from Immunotech (Miami, FL). The basal cell-specific cytokeratin antibody (mouse monoclonal, clone 34βE12, dilution 1:50) was from Enzo Biochem (Farmingdale, NY). Anti-cytokeratins 8 and 18 (mouse monoclonal, clone Cam 5.2, prediluted) was from Becton Dickinson (Franklin Lakes, NJ). Anti-topoisomerase II α (mouse monoclonal, clone AB-1, dilution 1:100) was from Calbiochem (San Diego, CA). Anti-GSTP1 (rabbit polyclonal, dilution 1:40,000) was from Medical and Biological Laboratories (Watertown, MA). Immunohistochemistry was performed using the Biotek Techmate 1000 (Ventana Medical Systems, Tucson, AZ) robotic immunostainer as described.38Silberman MA Partin AW Veltri RW Epstein JI Tumor angiogenesis correlates with progression after radical prostatectomy but not with pathologic stage in Gleason sum 5 to 7 adenocarcinoma of the prostate.Cancer. 1996; 79: 772-779Crossref Scopus (185) Google Scholar Briefly, all primary antibody incubations were carried out for 45 minutes at room temperature, except for GSTP1, which was at 4°C overnight. Biotinylated secondary antibody incubation was carried out for 30 minutes at room temperature. Histochemical localization using avidin-biotin horseradish peroxidase complex (ABC) was carried out using 3,3′-diaminobenzidine tetrahydrochloride (DAB) as the chromagen. Slides were couterstained with hematoxylin. For 34βE12 and Cam 5.2 cytokeratin staining, the sections were pretreated with protease type 27 (Sigma, St. Louis, MO. at 2 mg/ml for 20 minutes at 37°C before incubation with the primary antibodies. Formalin-fixed, paraffin-embedded tissues were obtained from The Johns Hopkins Hospital. All specimens were from radical prostatectomies (n = 42 patients) and consisted of portions of tissue dissected immediately after surgical removal and immersed in 10% neutral buffered formalin. Intensity of inflammation was recorded using a numerical 0–6 scale, with 0 representing no inflammation, 1–2 representing mild, 3–4 representing moderate, and 5–6 representing severe inflammation. All lesions were heterogeneous in terms of inflammation, in that different areas within an individual focus of atrophy had different amounts of inflammatory cells. Thus the scores recorded represented an overall average for each lesion. For each lesion we recorded the size and the following variables, using a 0–6 scale for each variable, where 0 is negative and 6 is the highest value: the extent of epithelial disruption, the relative number of intraluminal macrophages, and the extent of periglandular fibrosis. For each lesion we also recorded whether any part of the lesion was adjacent to or was away from high-grade PIN or carcinoma. Apoptosis was accessed by light microscopic examination for apoptotic bodies, using hematoxylin and eosin (H&E)-stained sections. For both PIA and adjacent normal epithelium, we recorded the number of apoptotic bodies within the epithelium per 20 high-power fields (hpf), using an Olympus BX-40 microscope with a 40× objective. The intensity of immunohistochemical staining for GSTP1 and Bcl-2 was scored on a numerical 0–6 scale system, with 0 representing background staining in benign normal-appearing nonatrophic secretory cells, 1–2 representing mild elevations, 3–4 representing moderate elevations, and 5–6 representing marked elevations. GSTP1 and Bcl-2 staining was also heterogeneous in that individual atrophy lesions contained areas with intense staining and other areas with somewhat less staining. Because lesions were heterogeneous, the overall score assigned represented the average for the entire lesion. For p27Kip1, AR, PSA, and PSAP, an identical scoring approach was used, except that negative numbers were used to indicate reduced expression. In 22 lesions, a Ki-67 labeling index was determined by counting the number of positively staining cells per total cells counted, with a minimum of 500 cells counted (range 500-2000). For this, the entire lesion was scanned at ×400 magnification with a BLISS imaging microscope (Bacus Laboratories, Lombard, IL). A minimum of five screen shots representing individual microscopic fields at ×400 were selected for counting at random. Each screen shot, consisting of a microscopic field, was copied and transferred to Adobe Photoshop 5.0 for Microsoft Windows 95/98. As the individual cells were counted, each nucleus was overlayed with a small green dot. In addition, cells staining positively for Ki-67 were overlayed with a red dot. By saving the file to disk, we obtained a permanent record of exactly which cells in the lesion were counted. In these 22 cases, normal epithelium away from the lesion was used as an internal reference for each lesion, and cells were similarly counted. Statistical analysis was carried out using the STATA 5.0 software package for Microsoft Windows 95. Many of the morphological features of PIA—focal prostatic atrophy in association with chronic inflammation—have been described.5Bennett BD Richardson PH Gardner WA Histopathology and cytology of prostatitis.in: Lepor H Lawson RK Prostate Diseases. W. B. Saunders Company, Philadelphia1993: 399-414Google Scholar, 10Franks LM Atrophy and hyperplasia in the prostate proper.J Pathol Bacteriol. 1954; 68: 617-621Crossref PubMed Scopus (149) Google Scholar, 13McNeal JE Prostate.in: Sternberg SS Histology for Pathologists. ed 2. Lippincott-Raven, Philadelphia1997: 997-1017Google Scholar, 16Gardner Jr, WA Culberson DE Atrophy and proliferation in the young adult prostate.J Urol. 1987; 137: 53-56PubMed Google Scholar The key identifying feature of focal prostatic atrophy is recognized at low power and consists of an overall hyperchromatic appearance of the involved glands, occurring often as a discrete focus among benign, normal-appearing glands (Figure 1). The majority of the PIA lesions (n = 41/55) were considered simple atrophy as described,20Ruska KM Sauvageot J Epstein JI Histology and cellular kinetics of prostatic atrophy.Am J Surg Pathol. 1998; 22: 1073-1077Crossref PubMed Scopus (118) Google Scholar which consisted of glands with variable acinar caliber (Figure 1, Figure 2, Figure 3, Figure 4, Figure 5). The majority of acini in simple atrophy acini were stellate in architecture and lacked papillary infoldings. Often the lesions contained corpora amylacea of varying sizes. Three of the lesions (n = 3/55) were classified as postatrophic hyperplasia (PAH),39Cheville JC Bostwick DG Postatrophic hyperplasia of the prostate. A histologic mimic of prostatic adenocarcinoma.Am J Surg Pathol. 1995; 19: 1068-1076Crossref PubMed Scopus (90) Google Scholar consisting of foci of crowded glands with small-caliber, round atrophic acini. Some of the lesions (n = 11/55) contained both PAH and simple atrophy.Figure 2Two cell layers in PIA. Medium-power view of section of PIA stained with the 34BE12 monoclonal antibody against basal cells. Arrows indicate atrophic secretory-type cells in the gland lumen. Arrowheads indicate basal cells. Inset: Higher power view of boxed area. Immunoperoxidase, ×200. Inset, ×400.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Expression of markers of proliferation and differentiation in PIA. A: Increased expression of proliferation associated marker, Ki-67, in secretory-type cells. B: Decreased expression of cyclin-dependent kinase inhibitor p27kip1 in secretory-type cells. C: Expression of PSA in secretory-type cells. A–C: Immunoperoxidase, ×200. Arrows indicate luminal cells.View Large Image Figure ViewerDownload Hi-res image
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