Jill A. Macoska

The Relationship Between Prostatic Intraepithelial Neoplasia and Prostate Cancer: Critical Issues

AbstractPurpose: Prostatic intraepithelial neoplasia (PIN) is often considered to be a premalignant lesion and the main precursor of invasive carcinoma of the prostate. We evaluated the evidence for and against PIN as a premalignant lesion and determined guidelines for the clinical management of PIN.Materials and Methods: Literature analysis of histopathological, morphometric, phenotypic and molecular genetic evidence of progression and of clinical findings regarding PIN was done. Literature searches were performed on MEDLINE with relevant key words.Results: PIN, like prostate cancer, occurs most frequently in the peripheral zone of the prostate and is usually located in close proximity to prostate cancer. The relative PIN and prostate cancer volumes vary inversely. Prostate specific antigen in cases of PIN appears to be intermediate between prostate cancer and normal levels, although this elevation may be explained by concomitant prostate cancer or benign prostatic hyperplasia. Deoxyribonucleic acid ploi...

Postatrophic Hyperplasia of the Prostate Gland : Neoplastic Precursor or Innocent Bystander?

Postatrophic hyperplasia (PAH) of the prostate gland often demonstrates overlapping histological features with prostatic adenocarcinoma (PCA). These features include small acinar growth and enlarged nuclei with prominent nucleoli. Recent work has demonstrated that PAH is a proliferative, noninvoluting lesion. PAH is also histologically distinct from simple atrophy (SA), which has intermediate- to large-sized glands, minimal cytoplasm, and inconspicuous nuclei. However, despite overlapping features between PAH and PCA, high-grade prostatic intraepithelial neoplasm (HGPIN) is still considered the only direct neoplastic precursor to PCA. HGPIN resembles PCA in its topographic distribution, cytological appearance, and molecular alterations including chromosome 8p loss and chromosome 8 centromeric gain. To examine the hypothesis that PAH is the earliest histologically distinct precursor to HGPIN or PCA, the frequency, distribution, proliferative state, and chromosome 8 gain of benign prostate, SA, PAH, HGPIN, and PCA were analyzed. Forty radical prostatectomy specimens from men with clinically localized PCA were systematically analyzed. Proliferation was determined by Ki-67 immunohistochemistry (MIB-1) on formalin-fixed, paraffin-embedded tissue and quantified by digital image analysis from a total of 5,510 sample areas with benign, SA, PAH, HGPIN, and PCA. A tissue microarray was constructed to evaluate 8c gain using interphase fluorescence in situ hybridization. SA foci (n = 129) and PAH foci (n = 114) were identified in the 40 cases of which 74% (95 of 129) and 88% (100 of 114) were seen in the peripheral zone, respectively (P = 0.006). PAH and SA were identified adjacent to PCA in 28% (32 of 114) and 14% (18 of 129) of foci examined, respectively (P = 0.007). The median number of proliferating nuclei increased significantly from benign (1.20%), SA (2.67%), PAH (3.62%), HGPIN (6.14%), to PCA (12.00%) (P < 0.001). The median percentage of nuclei with more than three centromeric probe signals (chromosome 8c gain) for SA, HGPIN, PAH, and PCA were 2.1, 2.8, 4.0, and 6.0%, respectively, as compared to benign prostate with 1.3% (P = 0.006). In conclusion, the present study identified a strong topographic association between PAH and PCA. PAH is also seen often to be closely associated with chronic inflammation. Proliferation of PAH is significantly greater than benign prostatic epithelium and SA but less than HGPIN or PCA. Gain of 8c is significantly greater in PAH than benign prostate, SA, and even HGPIN. These findings demonstrate a strong association between PAH and PCA, supporting its role as a neoplastic precursor.

Nanoroughened Surfaces for Efficient Capture of Circulating Tumor Cells without Using Capture Antibodies

Circulating tumor cells (CTCs) detached from both primary and metastatic lesions represent a potential alternative to invasive biopsies as a source of tumor tissue for the detection, characterization and monitoring of cancers. Here we report a simple yet effective strategy for capturing CTCs without using capture antibodies. Our method uniquely utilized the differential adhesion preference of cancer cells to nanorough surfaces when compared to normal blood cells and thus did not depend on their physical size or surface protein expression, a significant advantage as compared to other existing CTC capture techniques.

Genomic and Expression Analysis of the 8p11–12 Amplicon in Human Breast Cancer Cell Lines

Gene amplification is an important mechanism of oncogene activation in breast and other cancers. Characterization of amplified regions of the genome in breast cancer has led to the identification of important oncogenes including erbB-2/HER-2, C-MYC, and fibroblast growth factor receptor (FGFR) 2. Chromosome 8p11-p12 is amplified in 10–15% of human breast cancers. The putative oncogene FGFR1 localizes to this region; however, we show evidence that FGFR inhibition fails to slow growth of three breast cancer cell lines with 8p11-p12 amplification. We present a detailed analysis of this amplicon in three human breast cancer cell lines using comparative genomic hybridization, traditional Southern and Northern analysis, and chromosome 8 cDNA microarray expression profiling. This study has identified new candidate oncogenes within the 8p11-p12 region, supporting the hypothesis that genes other than FGFR1 may contribute to oncogenesis in breast cancers with proximal 8p amplification.

CXCL12 overexpression and secretion by aging fibroblasts enhance human prostate epithelial proliferation in vitro

The direct relationship between the aging process and the incidence and prevalence of both benign prostatic hyperplasia (BPH) and prostate cancer (PCa) implies that certain risk factors associated with the development of both diseases increase with the aging process. In particular, both diseases share an overly proliferative phenotype, suggesting that mechanisms that normally act to suppress cellular proliferation are disrupted or rendered dysfunctional as a consequence of the aging process. We propose that one such mechanism involves changes in the prostate microenvironment, which ‘evolves’ during the aging process and disrupts paracrine interactions between epithelial and associated stromal fibroblasts. We show that stromal fibroblasts isolated from the prostates of men 63–81 years of age at the time of surgery express and secrete higher levels of the CXCL12 chemokine compared with those isolated from younger men, and stimulate CXCR4‐mediated signaling pathways that induce cellular proliferation. These studies represent an important first step towards a mechanistic elucidation of the role of aging in the etiology of benign and malignant prostatic diseases.

Cancer-Specific Loss of β-Defensin 1 in Renal and Prostatic Carcinomas

In a previous large-scale gene expression profiling study of renal epithelial neoplasms, human β-defensin-1 (DEFB1) was found to be significantly down-regulated in conventional clear cell (renal) carcinoma. We have now completed an expanded expression analysis of this gene. We performed immunohistochemical analysis for the DEFB1 protein in clinical specimens of both renal cell carcinoma and prostate cancer. In a subset of prostate cancers, we performed laser capture microdissection and RT-PCR to correlate mRNA levels with protein levels. Overall, 82% of prostate cancers exhibit either complete loss of protein expression or only minimal expression, whereas the adjacent benign epithelium retained expression in all cases. Similarly, 90% of renal cell carcinomas show cancer-specific loss of DEFB1 protein. In the prostate cancer subset analysis, mRNA levels correlate with protein levels. We have thus demonstrated the cancer-specific down-regulation of DEFB1 in a large sample of prostatic and renal carcinomas and validated one of the key findings of previous cancer gene profiling studies of prostatic and renal neoplasia.

The Inflammatory Microenvironment of the Aging Prostate Facilitates Cellular Proliferation and Hypertrophy

Benign Prostatic Hypertrophy (BPH, also known as benign prostatic hyperplasia or benign prostatic enlargement), is one of the most common benign proliferative conditions associated with aging in men and is pathologically characterized by the proliferation of fibroblast/myofibroblast and epithelial cell types in the prostate. Previous studies from our laboratory have shown that the CXC-type chemokines, CXCL5 and CXCL12, are secreted by aging prostate stroma and promote both proliferative and transcriptional responses from prostate epithelial cells. Using array-based gene expression profiling and quantitative reverse-transcriptase polymerase chain reaction, we now show that the transcriptome of the aging prostate stroma is characterized by the up-regulation of several genes that encode secreted inflammatory mediators, including secreted CXC-type chemokines (CXCL1, CXCL2, CXCL5, CXCL6, CXCL12), interleukins (IL11, IL33), and transcripts with cytokine homology (CYTL1). At the protein level, ELISA experiments demonstrated that CXCL1, CXCL5, and CXCL6 were secreted by primary prostate stromal fibroblasts explanted from aging prostate stroma. Dose-response assays confirmed that, like CXCL5 and CXCL12, CXCL1 and CXCL6 promote low-level proliferative responses from both prostate stromal fibroblasts and epithelial cells. Taken together, these data suggest that inflammatory mediators are secreted by prostatic stroma consequent to aging, that the levels of these mediators are sufficient to promote low-level increases in the proliferative rate of both epithelial and stromal fibroblast cell types. Moreover, these processes may account for the low-level, but cumulative, proliferation of both epithelial and fibroblastic/myofibroblastic cell types that characterizes the aging-associated development of benign prostatic hypertophy.

8p22> loss concurrent with 8c gain is associated with poor outcome in prostate cancer

OBJECTIVES A critical issue in the management of prostate cancer is the ability to distinguish patients at risk of disease recurrence. The aim of this study was to determine whether specific physical alterations of chromosome 8 may be associated with disease recurrence and poor outcome using postoperative prostate-specific antigen (PSA) values as surrogate end points. METHODS To test this hypothesis, we examined paired normal and tumor radical prostatectomy tissues from 25 patients with prostate cancer for chromosome 8 alterations using dual fluorescence in situ hybridization with a fluorescein-labeled 8p22-specific (8p) cosmid probe and a rhodamine-labeled 8-centromere-specific (8c) probe. The probes were enumerated in 200 nuclei per tissue. RESULTS Of the 25 tumors examined, 22 demonstrated distinct classes of genetic alterations, or nuclear types, including disomy for 8p and 8c (1 tumor), loss of 8p and disomy for 8c (10 tumors), or loss of 8p concurrent with gain of 8c (11 tumors). The presence of even a small population of tumor nuclei characterized by the loss of 8p concurrent with the gain of 8c was correlated with poor tumor grade (P = 0.009), preoperative PSA values 11 ng/mL or higher (P = 0.022), high tumor stage (P = 0.086), and detectable, rising postoperative PSA values (P = 0.086). These observations are consistent with the hypothesis that a gain of chromosome 8 is associated with poor outcome in prostate cancer. CONCLUSIONS 8p loss concurrent with 8c gain may successfully predict disease recurrence and poor clinical outcome before the observation of detectable postoperative PSA values in patients with prostate cancer.

Homozygous and frequent deletion of proximal 8p sequences in human prostate cancers: Identification of a potential tumor suppressor gene site

By using tissue microdissection and polymerase chain reaction (PCR) techniques, we examined 85 prostate tumors that were paired with normal tissues from the same patients for allelic loss at 26 highly polymorphic microsatellite sequences, 21 spanning 8p and 5 localized to 8q. Sixty‐four tumors (75%) demonstrated loss of at least one 8p locus. Separate distal and proximal regions of deletion were observed as well as an intervening, staggered breakpoint. A novel region of homozygous deletion of sequences at the D8S87 locus was detected both by multiplex PCR and by fluorescence in situ hybridization within this breakpoint region. These data suggest that a tumor‐suppressor gene mapping to proximal 8p is deleted frequently and is likely to be important for tumorigenesis in prostate tumors. Genes Chromosomes Cancer 23:255–262,1998.

Prostatic Fibrosis is Associated with Lower Urinary Tract Symptoms

PURPOSE Current therapies for male lower urinary tract symptoms secondary to prostate enlargement prevent hormonal effects on prostate growth and inhibit smooth muscle contraction to ease bladder neck and urethral pressure. However, lower urinary tract symptoms can be refractory to these therapies, suggesting that additional biological processes not addressed by them may also contribute to lower urinary tract symptoms. Aging associated fibrotic changes in tissue architecture contribute to dysfunction in multiple organ systems. Thus, we tested whether such changes potentially have a role in impaired urethral function and perhaps in male lower urinary tract symptoms. MATERIALS AND METHODS Periurethral tissues were obtained from a whole prostate ex vivo and from 28 consecutive men treated with radical prostatectomy. Lower urinary tract symptoms were assessed using the American Urological Association symptom index. Prostate tissues were subjected to mechanical testing to assess rigidity and stiffness. Fixed sections of these tissues were evaluated for collagen and elastin content, and glandularity to assess fibrosis. Statistical analysis included the Student t test and calculation of Pearson correlation coefficients to compare groups. RESULTS Periurethral prostate tissues demonstrated nonlinear viscoelastic mechanical behavior. Tissue from men with lower urinary tract symptoms was significantly stiffer (p = 0.0016) with significantly higher collagen content (p = 0.0038) and lower glandularity than that from men without lower urinary tract symptoms (American Urological Association symptom index 8 or greater vs 7 or less). CONCLUSIONS Findings show that extracellular matrix deposition and fibrosis characterize the periurethral prostate tissue of some men with lower urinary tract symptoms. They point to fibrosis as a factor contributing to lower urinary tract symptom etiology.