Analysis of alpha-methylacyl-CoA racemase (P504S) expression in high-grade prostatic intraepithelial neoplasia

Anti-tumor activity of a T-helper 1 multiantigen vaccine in a murine model of prostate cancer

Prostate cancer is one of the few malignancies that includes vaccination as a treatment modality. Elements of an effective cancer vaccine should include the ability to elicit a Type I T-cell response and target multiple antigenic proteins expressed early in the disease. Using existing gene datasets encompassing normal prostate tissue and tumors with Gleason Score ≤ 6 and ≥ 8, 10 genes were identified that were upregulated and conserved in prostate cancer regardless of the aggressiveness of disease. These genes encoded proteins also expressed in prostatic intraepithelial neoplasia. Putative Class II epitopes derived from these proteins were predicted by a combination of algorithms and, using human peripheral blood, epitopes which selectively elicited IFN-γ or IL-10 dominant antigen specific cytokine secretion were determined. Th1 selective epitopes were identified for eight antigens. Epitopes from three antigens elicited Th1 dominant immunity in mice; PSMA, HPN, and AMACR. Each single antigen vaccine demonstrated significant anti-tumor activity inhibiting growth of implanted Myc-Cap cells after immunization as compared to control. Immunization with the combination of antigens, however, was superior to each alone in controlling tumor growth. When vaccination occurred simultaneously to tumor implant, multiantigen immunized mice had significantly smaller tumors than controls (p = 0.002) and a significantly improved overall survival (p = 0.0006). This multiantigen vaccine shows anti-tumor activity in a murine model of prostate cancer.

CDK19 as a diagnostic marker for high-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (HGPIN) is a facultative precursor lesion of prostate cancer (PCa). Multifocal HGPIN in needle biopsies in the absence of PCa indicates a higher risk of cancer detection in subsequent biopsies. Therefore, a reliable diagnosis of HGPIN is of high clinical relevance guiding the management of patients with cancer-negative biopsies. Detection of HGPIN is merely based on morphological features while biomarkers aiding in the diagnosis of HGPIN and its differentiation from benign glands and other glandular lesions are lacking yet. Here, we investigated the expression of CDK19 by immunohistochemistry on prostate needle biopsies of 140 patients who were all diagnosed with PCa using whole tissue sections, and compared CDK19 levels between HGPIN, PCa and adjacent benign glands. In addition, CDK19 was compared to AMACR expression in a subset of intraductal carcinomas (IDC) on radical prostatectomy (RP) specimens. HGPIN was present in 65.7% of biopsies and in 88% associated to adjacent PCa. CDK19 overexpression defined as moderate to high CDK19 expression visible at low magnification was found in 82.6% of HGPIN. In contrast, 89.3% of benign glands were CDK19-negative or demonstrated only low CDK19 expression highlighting a high sensitivity and specificity to accurately detect HGPIN based on CDK19 expression levels. CDK19 was overexpressed in 59% of PCa but did not correlate significantly with the expression of intermingled HGPIN. On RP, CDK19 and AMACR showed no significant difference in the detection rate of IDC. In summary, assessment of CDK19 facilitates accurate and simplified diagnosis of HGPIN with high sensitivity and specificity and aides the differentiation to non-neoplastic glandular alterations. Considering the high clinical significance of diagnosis HGPIN that still has a limited reproducibility among pathologists we suggest CDK19 as diagnostic biomarker for HGPIN.

Glyoxalase 1 Expression as a Novel Diagnostic Marker of High-Grade Prostatic Intraepithelial Neoplasia in Prostate Cancer

Glyoxalase 1 (GLO1) is an enzyme involved in the detoxification of methylglyoxal (MG), a reactive oncometabolite formed in the context of energy metabolism as a result of high glycolytic flux. Prior clinical evidence has documented GLO1 upregulation in various tumor types including prostate cancer (PCa). However, GLO1 expression has not been explored in the context of PCa progression with a focus on high-grade prostatic intraepithelial neoplasia (HGPIN), a frequent precursor to invasive cancer. Here, we have evaluated GLO1 expression by immunohistochemistry in archival tumor samples from 187 PCa patients (stage 2 and 3). Immunohistochemical analysis revealed GLO1 upregulation during tumor progression, observable in HGPIN and PCa versus normal prostatic tissue. GLO1 upregulation was identified as a novel hallmark of HGPIN lesions, displaying the highest staining intensity in all clinical patient specimens. GLO1 expression correlated with intermediate-high risk Gleason grade but not with patient age, biochemical recurrence, or pathological stage. Our data identify upregulated GLO1 expression as a molecular hallmark of HGPIN lesions detectable by immunohistochemical analysis. Since current pathological assessment of HGPIN status solely depends on morphological features, GLO1 may serve as a novel diagnostic marker that identifies this precancerous lesion.

Application and Pitfalls of Immunohistochemistry in Diagnosis of Challenging Genitourinary Cases

CONTEXT.—

Immunohistochemistry (IHC) has become increasingly important in the evaluation of pathologic conditions in the genitourinary (GU) organs. In addition to careful evaluation of hematoxylin-eosin sections and generation of a differential diagnosis, choosing the optimal panel of IHC markers becomes even more important when the biopsy material is very limited. The following summary of our experience supplemented with relevant literature review exemplifies how to use IHC to facilitate pathologic diagnosis in the GU system.

OBJECTIVE.—

To describe our experience with the most common immunohistochemical markers used in GU pathology.

DATA SOURCES.—

Institutional experience and literature search comprise our data sources.

CONCLUSIONS.—

Application of IHC provides enormous benefits to the interpretation of GU pathologic conditions, including benign and malignant lesions. However, both insufficient and excessive types of use of IHC, as well as incorrect interpretations in common and rare GU conditions, could present pitfalls in diagnosis.

Molecular evidence supporting the precursor nature of atypical adenomatous hyperplasia of the prostate

Atypical adenomatous hyperplasia (AAH) of the prostate is characterized by lobular proliferation of closely packed small acini. It is hypothesized that AAH is a precursor lesion for low-grade prostate cancer arising from the transition zone. Telomere dysfunction is common during malignant transformation of epithelia. In this study, we investigate telomere shortening in AAH (n = 93), high-grade prostatic intraepithelial neoplasia (HGPIN) ( n = 68), and prostatic adenocarcinoma (PCA) ( n = 70) using quantitative fluorescence in situ hybridization. Twenty percent (19 of 93) of AAH specimens, 68% (46 of 68) of HGPIN, and 83% (58 of 70) of PCA showed significant telomere shortening. Thirty-two percent of AAH lesions had α-methylacyl-CoA racemase (AMACR) expression, a sensitive and specific marker for HGPIN and PCA. AMACR expression in AAH was seen more frequently in AAH foci with telomere shortening or coexisting PCA. Our findings indicate that a subset of AAH lesions have telomere shortening and AMACR expression, suggesting that these foci may be precursors for PCA.

Immunohistochemical Pitfalls in Genitourinary Pathology: 2018 Update

Immunohistochemistry may be a very useful adjunct to morphologic diagnosis in many areas of surgical pathology, including genitourinary pathology. In this review, we address common diagnostic dilemmas where immunophenotypic analysis may be utilized and we highlight pitfalls specific to each scenario. For prostate, we review the diagnosis of limited prostatic adenocarcinoma and the distinction of high-grade prostatic adenocarcinoma from urothelial carcinoma. We also cover markers of urothelial lineage in the diagnosis of metastatic carcinoma of unknown primary site. In the kidney, distinction of poorly differentiated renal cell carcinoma from urothelial carcinoma and epithelioid angiomyolipoma, adjuncts to the recognition of hereditary renal neoplasia, and the diagnosis of metastatic renal cell carcinoma are discussed. Finally, for testis we address distinction of germ cell tumors from sex cord-stromal tumors, as well as the diagnosis of metastatic germ cell tumors.

Markers of clinical utility in the differential diagnosis and prognosis of prostate cancer

Molecular diagnostics is a rapidly evolving area of surgical pathology, that is gradually beginning to transform our diagnostical procedures for a variety of tumors. Next to molecular prognostication that has begun to complement our histological diagnosis in breast cancer, additional testing to detect targets and to predict therapy response has become common practice in breast and lung cancer. Prostate cancer is a bit slower in this respect, as it is still largely diagnosed and classified on morphological grounds. Our diagnostic immunohistochemical armamentarium of basal cell markers and positive markers of malignancy now allows to clarify the majority of lesions, if applied to the appropriate morphological context (and step sections). Prognostic immunohistochemistry remains a problematic and erratic yet tempting research field that provides information on tumor relevance of proteins, but little hard data to integrate into our diagnostic workflow. Main reasons are various issues of standardization that hamper the reproducibility of cut-off values to delineate risk categories. Molecular testing of DNA-methylation or transcript profiling may be much better standardized and this review discusses a couple of commercially available tests: The ConfirmDX test measures DNA-methylation to estimate the likelihood of cancer detection on a repeat biopsy and may help to reduce unnecessary biopsies. The tests Prolaris, OncotypeDX Prostate, and Decipher all are transcript tests that have shown to provide prognostic data independent of clinico-pathological parameters and that may aid in therapy planning. However, further validation and more comparative studies will be needed to clarify the many open questions concerning sampling bias and tumor heterogeneity.

Prostate cancer: diagnostic criteria and role of immunohistochemistry

The diagnosis of prostate cancer is based on microscopic criteria. Presently, prostate needle biopsy interpretation can be a challenge for the pathologist due to the increased number of specimens with limited amount of suspicious glands and minimal atypia. It is critical for the pathologist to have an organized methodical approach when considering the morphological features enabling a definitive diagnosis of prostate cancer. Although several diagnostic criteria and supportive features have been advocated, only few findings are absolutely specific and diagnostic of prostate cancer. The diagnosis of prostate cancer relies on a combination of architectural and cytological features that are reviewed in detail herein. Infiltrative growth pattern, prominent nucleoli and lack of basal cells are the most useful diagnostic criteria. Perineural invasion, glomerulation and mucinous fibroplasia are pathognomonic features of prostate cancer, although uncommon on small prostate cancer foci. The role of immunohistochemistry in establishing a diagnosis of limited prostate is addressed.

Systems pathology by multiplexed immunohistochemistry and whole-slide digital image analysis

The paradigm of molecular histopathology is shifting from a single-marker immunohistochemistry towards multiplexed detection of markers to better understand the complex pathological processes. However, there are no systems allowing multiplexed IHC (mIHC) with high-resolution whole-slide tissue imaging and analysis, yet providing feasible throughput for routine use. We present an mIHC platform combining fluorescent and chromogenic staining with automated whole-slide imaging and integrated whole-slide image analysis, enabling simultaneous detection of six protein markers and nuclei, and automatic quantification and classification of hundreds of thousands of cells in situ in formalin-fixed paraffin-embedded tissues. In the first proof-of-concept, we detected immune cells at cell-level resolution (n = 128,894 cells) in human prostate cancer, and analysed T cell subpopulations in different tumour compartments (epithelium vs. stroma). In the second proof-of-concept, we demonstrated an automatic classification of epithelial cell populations (n = 83,558) and glands (benign vs. cancer) in prostate cancer with simultaneous analysis of androgen receptor (AR) and alpha-methylacyl-CoA (AMACR) expression at cell-level resolution. We conclude that the open-source combination of 8-plex mIHC detection, whole-slide image acquisition and analysis provides a robust tool allowing quantitative, spatially resolved whole-slide tissue cytometry directly in formalin-fixed human tumour tissues for improved characterization of histology and the tumour microenvironment.

Current significance of the finding of high grade prostatic intraepithelial neoplasia in the prostate biopsy

INTRODUCTION

High grade prostatic intraepithelial neoplasia (HGPIN) is regarded as a precursor of prostate cancer (PC). However, its relationship to cancer has changed throughout the literature, being currently poorly defined and remains controversial for urologists in their clinical practice. Because of his frequency and the impact on patient outcomes that the lack of consensus clinical attitude could carry out, it seems advisable to review the understanding of this disease.

OBJECTIVE

The aim of this literature review is to summarize the main features of this entity (histopathology, molecular, epidemiological) and evaluate their relationship with prostate adenocarcinoma, explaining the variation of incidence seen in the literature and the clinical significance of their finding.

MATERIAL AND METHODS

Review of the literature, based on the research and analysis of publications found in Pubmed with the words "prostate" and "intraepithelial neoplasms".

RESULTS

The HGPIN detection rate has increased to the extent that it has increased the number of punctures in prostate biopsies. With the current biopsy schemes (10-12 punctures), the detection rate of PC in repeat biopsies is similar in patients with and without isolated HGPIN. However, HGPIN multifocality predicts increased risk of PC detection in repeat biopsy.

CONCLUSION

HGPIN detection is common with current biopsy schemes. Its genetic relationship with PC is clear and its multifocality is the most important predictor factor of PC.

Basal cell hyperplasia (BCH) versus high grade prostatic intraepithelial neoplasia (HGPIN) in tiny prostatic needle biopsies: Unusual diagnostic dilemma

BACKGROUND

Histopathological differentiation between BCH and HGPIN in prostatic needle biopsies is a diagnostic challenge. The gold standard for detection of HGPIN and BCH is histopathological examination; however subjectivity in interpretation and tiny volume of obtained tissue hamper reliable diagnosis.

AIMS

The aim of this study was to assess usefulness of using the p63 and p504s to solve this problem. Although the use of p63 and p504s is now well established in differentiation between preneoplastic and neoplastic prostatic lesions, their usefulness in tiny tissue material is, however, not fully studied.

METHODS

The study included a spectrum of 30 prostatic needle biopsies (5 BCH, 10 HGPIN, 10 indefinite luminal proliferations where BCH and HGPIN could not be distinguished from each other and 5 adenocarcinomas). H&E stained sections were examined for histopathological features. Other sections were stained immunohistochemically with p63 and p504s.

RESULTS

The mean age of patients was 69 (SD=7.6) years. PSA range was 1.3-2.7 ng/ml. Ultrasongraphic findings were unremarkable. All BCH showed p504s-/p63+ pattern, All HGPIN had p504s+/p63+ pattern while carcinomas were p504s+/p63-. After immunostaining combined with histopathological features; the 10 indefinite specimens could be diagnosed as 4 BCH and 6 HGPIN. The article explains how applying this staining pattern on the challenging specimens, combined with histopathological features, can be helpful in proper identification of prostatic proliferations.

When is prostate cancer really cancer?

Several investigators have challenged the idea that low-grade cancers are a cause for concern, suggesting that the term cancer should not be applied to these tumors. This article reviews the defining features of cancer, and the diagnostic and prognostic classification systems currently used for prostate cancer. Logical, morphologic, and molecular evidence is presented to show that low-grade prostate cancers are correctly classified as cancer. The authors suggest, however, that 6 out of 10 on an aggressiveness scale is inappropriate for indolent cancer, and that a proposed reinterpretation of Gleason grading categories is a more logical way to address overtreatment.

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

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

Correlation of urine TMPRSS2:ERG and PCA3 to ERG+ and total prostate cancer burden

ERG rearrangements (most commonly transmembrane protease, serine 2 [TMPRSS2]:ERG [T2:ERG] gene fusions) have been identified in approximately 50% of prostate cancers . Quantification of T2:ERG in postdigital rectal examination urine, in combination with PCA3, improves the performance of serum prostate-specific antigen for prostate cancer prediction on biopsy. Here we compared urine T2:ERG and PCA3 scores with ERG+ (determined with immunohistochemical analysis) and total prostate cancer burden in 41 mapped prostatectomies. Prostatectomies had a median of 3 tumor foci (range, 1-15) and 2.6 cm of summed linear tumor dimension (range, 0.6-7.1 cm). Urine T2:ERG score correlated most with summed linear ERG+ tumor dimension and number of ERG+ foci (r(s) = 0.68 and 0.67, respectively, both P < .001). Urine PCA3 score showed weaker correlation with both number of tumor foci (r(s) = 0.34, P = .03) and summed linear tumor dimension (r(s) = 0.26, P = .10). In summary, we demonstrate a strong correlation between urine T2:ERG score and total ERG+ prostate cancer burden at prostatectomy, consistent with high tumor specificity.

Precursors of prostate cancer

High-grade prostatic intraepithelial neoplasia (PIN) is the only accepted precursor of prostatic adenocarcinoma, according to numerous studies of animal models and man; other proposed precursors include atrophy and malignancy-associated changes (with no morphologic changes). PIN is characterized by progressive abnormalities of phenotype and genotype that are intermediate between benign prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. The only method of detection of PIN is biopsy because it does not significantly elevate serum prostate-specific antigen concentration and cannot be detected by ultrasonography. The mean incidence of PIN in biopsies is 9% (range, 4%-16%), representing about 115,000 new cases of isolated PIN diagnosed each year in the United States. The clinical importance of PIN is its high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent carcinoma, especially when multifocal or observed in association with atypical small acinar proliferation (ASAP). Carcinoma develops in most patients with PIN within 10 years. Androgen deprivation therapy and radiation therapy decrease the prevalence and extent of PIN, suggesting that these forms of treatment may play a role in prevention of subsequent cancer. Multiple clinical trials to date of men with PIN have had modest success in delaying or preventing subsequent cancer.

In situ and intraductal epithelial proliferations of prostate: definitions and treatment implications. Part 1: Prostatic intraepithelial neoplasia

What's known on the subject? and What does the study add? In the era of extended biopsy sampling of the prostate, multifocal high-grade prostatic intraepithelial neoplasia (HGPIN) is associated with a significantly higher rate of cancer diagnosis than unifocal HGPIN or a benign diagnosis. In addition, the cancers that are subsequently diagnosed in men with HGPIN on their initial biopsy tend to be smaller, lower grade and more commonly organ-confined. This has led to a reappraisal of the need and timing of repeat biopsies. The present paper provides a series of recommendations on the optimal timing of repeat biopsies in men with HGPIN on biopsy, based on the current available evidence. This is the first of a two part series reviewing the nature and clinical significance of in situ cellular proliferations in the prostate gland. This first part examines prostatic intraepithelial neoplasia (PIN), while the second part in the next supplement discusses intraductal carcinoma and ductal adenocarcinoma of the prostate. PIN is a precursor lesion in the development of some forms of adenocarcinoma of the prostate. In the 1990 s, high-grade PIN (HGPIN) on biopsy was a significant predictor of carcinoma, but this was due to incomplete sampling with sextant biopsies. With more extensive sampling in the last decade, the likelihood of identifying cancer after a diagnosis of HGPIN is not significantly different from a benign diagnosis. In several recent studies, it is now recognised that multifocal HGPIN is a better predictor of cancer than unifocal HGPIN. Most cases of cancer will be detected in the vicinity of the HGPIN, but up to 40% of cancers will occur in different sextants. In assessing potential markers for carcinoma in men with HGPIN on biopsy, α-methylacyl coenzyme-A racemase (AMACR) has emerged as a promising diagnostic tool. HGPIN with strong staining for AMACR is associated with a higher rate of cancer detection in subsequent biopsies compared with AMACR-negative HGPIN. Also, AMACR positivity in HGPIN is more commonly seen adjacent to carcinoma, and this may provide guidance as to the site of future biopsies.

The utility of ERG/P63 double immunohistochemical staining in the diagnosis of limited cancer in prostate needle biopsies

Diagnosis of limited cancer can be challenging in prostate needle biopsies, and immunohistochemistry is commonly used in such settings. Recently, TMPRSS2:ERG gene rearrangement was found to be highly specific for and detected in approximately 50% of prostate cancer. Positive immunohistochemical staining with a novel anti-ERG antibody highly correlated with TMPRSS2:ERG gene rearrangement status. We developed a double immunohistochemical staining containing both erythroblastosis virus E26 oncogen (ERG) and basal cell marker P63 antibodies and evaluated its use in the diagnosis of limited cancer in prostate needle biopsies. A total of 77 prostate needle biopsies containing cancer occupying <1 mm of the length of only 1 core of the entire biopsy set were stained with the double stain containing ERG and P63 antibodies. ERG positivity and its staining intensity in cancerous and other noncancerous lesions were evaluated. ERG expression was detected in 42% (32 of 77) of cases, with strong, moderate, and weak staining intensity in 72%, 16%, and 12% of cases. The staining was uniform in 84% of cases and heterogeneous in 16% of cases with different staining intensities in >10% of cancerous cells. High-grade prostatic intraepithelial neoplasia was present in 17 cases, and in 5 (29%) cases ERG was positive in high-grade prostatic intraepithelial neoplasia glands, which were all immediately adjacent to or intermingled with ERG-positive cancerous glands. In 4 additional cases, positive ERG staining was found in morphologically benign glands, which were also immediately adjacent to or intermingled with ERG-positive cancerous glands. All other benign lesions distant from cancerous glands, including simple and partial atrophy, were negative for ERG. P63 was negative in all cancerous glands and positive in noncancerous lesions. The P63/ERG double immunostain combines the high sensitivity of P63 and the high specificity of ERG and may be potentially useful in the work-up of difficult prostate biopsies. The high specificity of ERG for the presence of cancer may have important implications for prostate biopsy interpretation and needs to be further validated in larger prospective studies.

Premalignant and malignant prostate lesions: pathologic review

BACKGROUND

High-grade prostatic intraepithelial neoplasia (HGPIN) is currently the only recognized premalignant lesion of prostatic carcinoma.

METHODS

This review article discusses HGPIN, its link to prostatic adenocarcinoma, and the significance of its presence on needle biopsy. The criteria and clinical impact of the diagnosis of atypical small acinar proliferation on needle biopsy are reviewed. Certain subtypes of prostate cancer that are not associated with HGPIN are of clinical relevance, and the unique clinicopathologic features of these subtypes are discussed. Histologic variants of prostatic adenocarcinoma with distinct cell types are also described.

RESULTS

HGPIN is the only known pathologic factor currently available to distinguish which patients may be at risk for detecting carcinoma on repeat biopsy. Histologic variants are recognized due to the inference of a particular Gleason grade pattern associated with the cell type, hence affecting prognosis. Typically, pure forms of these histologic variants are associated with worse prognosis due to the associated high Gleason grades.

CONCLUSIONS

HGPIN has a strong association with acinar-type prostatic adenocarcinoma. HGPIN and acinar-type prostatic adenocarcinoma both show similar molecular alterations, providing further evidence of their association.

Cancer biomarker discovery: the entropic hallmark

Background

It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods.

Methodology/Principal Findings

Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer.

Conclusions/Significance

We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.

Identification of a cell of origin for human prostate cancer

Luminal cells are believed to be the cells of origin for human prostate cancer, because the disease is characterized by luminal cell expansion and the absence of basal cells. Yet functional studies addressing the origin of human prostate cancer have not previously been reported because of a lack of relevant in vivo human models. Here we show that basal cells from primary benign human prostate tissue can initiate prostate cancer in immunodeficient mice. The cooperative effects of AKT, ERG, and androgen receptor in basal cells recapitulated the histological and molecular features of human prostate cancer, with loss of basal cells and expansion of luminal cells expressing prostate-specific antigen and alpha-methylacyl-CoA racemase. Our results demonstrate that histological characterization of cancers does not necessarily correlate with the cellular origins of the disease.

Alpha-methylacyl-CoA racemase (AMACR) in fine-needle aspiration specimens of prostate lesions

The elevated expression of P504S gene and its product alpha-methylacyl-CoA racemase (AMACR) can serve as a molecular marker for prostate cancer. The goal of this study is to investigate P504S/AMACR expression in fine-needle aspiration smears and correlate it with cytological diagnosis. Immunocytochemistry was performed in 35 patients with morphological diagnosis of prostate carcinoma (n = 16), atypia (n = 15), and benign hyperplasia (n = 4). Among 16 malignant cases there were two low-grade, eight intermediate, and six high-grade prostate carcinomas. Cytoplasmic positivity is analyzed qualitatively as predominantly diffuse or focal and quantitatively as <5%, 5-50%, and >50% of cells. Benign cases showed no P504S/AMACR expression. Positive staining was recorded in 75% of malignant cases, but in the majority of them it was weak and focal or diffuse and in a small amount of cells. The most intensive staining was seen in low-grade carcinomas and some atypical cases. This observation indicates a correlation between P504S/AMACR expression and differentiation of cells. P504S/AMACR staining might be of great value in cytodiagnosis of prostate lesions as well as an example of the characterization of cells at the molecular level using fresh tissue obtained by fine-needle aspiration.

Usefulness of cytokeratin 5/6 and AMACR applied as double sequential immunostains for diagnostic assessment of problematic prostate specimens

We evaluated the usefulness of double immunohistochemical staining for cytokeratin (CK)5/6 and alpha-methylacyl coenzyme A racemase (AMACR) applied sequentially on 1 slide by assessing 223 foci in 110 consecutive prostate specimens. Double-chromogen reaction was used to visualize the antibodies: brown for CK5/6 and red for AMACR. Staining was scored as diffuse, focal, or negative. To establish the diagnosis, CK5/6 and AMACR were correlated with the morphologic features. All cancers lacked CK5/6 staining (100% specificity). AMACR showed diffuse or focal positivity in cancer, high-grade prostatic intraepithelial neoplasia, and atypia in 96.8% (120/124), 85% (22/26), and 80% (16/20) of cases, respectively. In atypical cases, diagnosis was because of non-immunohistochemical staining reasons in 80% of cases. In adenosis (n = 14), AMACR was diffusely positive in 4 cases (29%). Double immunohistochemical staining for CK5/6 and AMACR is a simple assay to perform and may be used as an alternative to antibody cocktails for routine evaluation of problematic prostate specimens.

[Trends in prostate biopsy interpretation]

Driven by the pressure of increasing use of PSA screening, cancer diagnosis based on histopathology has been constantly improved. When appropriate quality standards for obtaining a biopsy specimen and for tissue preparation are upheld, even the smallest tumour foci can be identified with certainty. Efforts to standardize the Gleason grading should also help to render assessments of tumour biology more precise. In addition, subtle diagnosis of precancerous or cancer-associated lesions will permit more exact prognoses of existing cancer risk to be made. There are still weak points: reliable recognition of clinically insignificant carcinomas and the danger of overtreatment. Further research activity on this topic is needed.

Precursor lesions to prostatic adenocarcinoma

High-grade prostatic intraepithelial neoplasia (PIN) is the one well-documented precursor to adenocarcinoma of the prostate. This review article defines both low- and high-grade PIN. Unusual variants of high-grade PIN are illustrated. Benign lesions that may be confused with high-grade PIN, including central zone histology, clear cell cribriform hyperplasia, and basal cell hyperplasia are described and illustrated. High-grade PIN is also differentiated from invasive acinar (usual) and ductal adenocarcinoma. The incidence of high-grade PIN, its relationship to carcinoma (including molecular findings), and risk of cancer on rebiopsy are covered in detail. Finally, intraductal carcinoma of the prostate, a controversial entity, is discussed and differentiated from high-grade PIN.

PTOV1 expression predicts prostate cancer in men with isolated high-grade prostatic intraepithelial neoplasia in needle biopsy

PURPOSE

To analyze the expression of PTOV1 in high-grade prostatic intraepithelial neoplasia (HG-PIN) and to explore its usefulness to predict prostate cancer in patients with isolated HG-PIN in needle biopsy (prostate needle biopsy).

EXPERIMENTAL DESIGN

PTOV1 expression in HG-PIN lesions from 140 patients was analyzed by immunohistochemistry in a semiquantitative manner (Histo-score). HG-PIN derived from 79 radical prostatectomies for prostate cancer and from 11 cistoprostatectomies for bladder cancer without prostate cancer were used as positive and negative controls, respectively. Fifty patients with HG-PIN without concomitant cancer at their first prostate needle biopsy were chosen as the study group. Patients were followed by a mean of 2.5 repeated prostate needle biopsies (1-5), during a mean period of 12.4 months (1-39).

RESULTS

PTOV1 expression in HG-PIN from radical prostatectomies showed a significantly higher Histo-score (162.6) compared with specimens from cistoprostatectomies (67.0). In the study group, PTOV1 expression was significantly higher in samples with cancer in the follow-up (11 patients, 22%) compared with samples in which cancer was not detected (151.4 versus 94.6). PTOV1 expression was the only independent predictor of cancer in the multivariate analysis and the area under the curve was 0.803 (95% confidence interval, 0.728-0.878). A threshold of 100 for PTOV1 expression provided 90.9% sensitivity, 51.3% specificity, 34.5% positive predictive value, and 95.2% negative predictive value.

CONCLUSIONS

PTOV1 is overexpressed in HG-PIN associated with cancer and is a potential marker for studying the carcinogenesis and progression of prostate cancer. Prostate needle biopsy with PTOV1 expression in HG-PIN above a threshold of 100 should be repeated immediately for the likely presence of undiagnosed cancer.

p63 in prostate biology and pathology

The identification of stem cells and differentiation programs regulating the development and maintenance of the normal prostate epithelium is essential for the identification of the cell type(s) and molecular alterations involved in the development and propagation of prostate cancer (CaP). The p53-homologue p63 is highly expressed in normal prostate basal cells and is a clinically useful biomarker for the diagnosis of CaP. Importantly, p63 has been shown to play a critical role in prostate development. Recent experimental evidence also suggests that this gene is essential for normal stem cell function in the prostate as well as other epithelial organs. Future studies aimed at better defining the role of p63 in the renewal of the adult prostate epithelium are likely to shed new light on the mechanisms involved in prostate carcinogenesis.

[New markers in prostate biopsies]

The use of serum prostate-specific antigen screening to facilitate early detection of prostate cancer has resulted in a dramatic increase in the number of prostate needle core biopsies which pathologists must examine. This has been accompanied by a strong increase in the number of biopsies with ambiguous lesions, and an unequivocal diagnosis of malignancy is difficult to render, especially in the case of limited foci or in small atypical acinar lesions. When assessing small foci of atypical glands upon needle biopsy, the pathologist searches for differences between the benign glands and atypical glands in terms of usual morphological features and in such cases, immunohistochemical stains for basal cell markers such as 34betaE12 antibody or antibodies directed against cytokeratin 5 and 6 and more recently p63 may be a useful adjuvant to identify basal cells which are typically present in benign glands but absent in prostatic carcinoma. However several benign mimickers of prostate carcinoma, including atrophy, atypical adenomatous hyperplasia, nephrogenic adenoma can stain negatively with these antibodies and thus a negative basal cell marker immunostain alone does not exclude a diagnosis of benignancy. Alpha-methyl-coenzyme-A-racemase (AMACR) a new sensitive marker of prostate carcinoma, can be useful in confirming ambiguous lesion suspected for malignancy. Although, as with any immunohistochemical studies, problems exist in terms of both sensitivity and specificity. The aim of this review is to describe the histological features of prostatic carcinoma in case of small focus, and discuss the application of these new prostatic markers in the light of the current literature to highlight the best practice guidelines.

Prognostic significance of alpha-methylacyl-coA racemase among men with high grade prostatic intraepithelial neoplasia in prostate biopsies

PURPOSE

Serum prostate specific antigen screening has increased the number of prostate biopsies performed increasing the number of patients with high grade prostatic intraepithelial neoplasia. The criteria for re-biopsy are not standardized but may be refined by the identification of novel biomarkers demonstrating prognostic significance. Alpha-methylacyl-CoA racemase is a robust marker of prostate cancer and is expressed in a subset of high grade prostatic intraepithelial neoplasia. This study evaluates the prognostic significance of alpha-methylacyl-coA racemase positive high grade prostatic intraepithelial neoplasia glands in prostate biopsies.

MATERIALS AND METHODS

Immunohistochemical staining with alpha-methylacyl-coA racemase and p63 was examined in a selected group of 62 patients with a diagnosis of high grade prostatic intraepithelial neoplasia on initial prostate biopsy, of which on repeat biopsy 32 had no carcinoma and 30 had prostate cancer. There was no significant difference in age, number of cores sampled or prostate specific antigen history between the 2 outcome groups (ANOVA p >0.9). High grade prostatic intraepithelial neoplasia glands in each case were evaluated for alpha-methylacyl-coA racemase and p63.

RESULTS

Reactivity for alpha-methylacyl-coA racemase was found in 27 of the 62 cases examined. Fisher's exact analysis revealed that patients with at least 1 alpha-methylacyl-coA racemase positive high grade prostatic intraepithelial neoplasia gland were 5.2 times more likely to have a subsequent diagnosis of prostate cancer on repeat biopsy than those without any alpha-methylacyl-coA racemase positive high grade prostatic intraepithelial neoplasia glands (p = 0.0044). No correlation was found between alpha-methylacyl-coA racemase positivity and any other clinical variable.

CONCLUSIONS

This is the first study to our knowledge to illustrate that alpha-methylacyl-coA racemase reactivity in high grade prostatic intraepithelial neoplasia may be useful to refine re-biopsy criteria and assist in clinical management decisions.

Heterogeneous expression of alpha-methylacyl-CoA racemase in prostatic cancer correlates with Gleason score

AIMS

Alpha-methylacyl-CoA racemase (AMACR) is a sensitive and specific immunohistochemical marker of prostatic malignancy, staining 80-100% of prostatic cancers with absent staining in benign glands. However, positive staining in benign conditions as well as low rates of AMACR reactivity in prostatic cancer variants have been described. Preliminary use of AMACR immunohistochemistry in our institution has suggested lower specificity and sensitivity for prostatic cancer than initially proposed. The aim of this study was to establish true rates of AMACR reactivity in prostatic cancer and benign prostatic hyperplasia (BPH).

METHODS AND RESULTS

AMACR immunohistochemistry was performed on sections from 57 prostatic cancers and 44 BPH resections. Ninety-one percent of cancers were AMACR+, with diffuse (> 75%) tumour staining in 53% of cases. Thirty-eight percent of tumours showed heterogeneous expression (1-75% tumour staining). This was significantly correlated with increased Gleason score. High-grade prostatic intraepithelial neoplasia (PIN) was AMACR+ in 87% of cancers. Eleven percent of BPH showed moderate or strong staining in benign glands, focally mimicking the malignant staining pattern.

CONCLUSIONS

This study confirms heterogeneous AMACR expression in prostatic cancer and shows a correlation with Gleason score. Positive staining in BPH is also documented, thus emphasizing the importance of interpreting AMACR immunohistochemistry in the context of other findings in a diagnostic setting.

Prostatic intraepithelial neoplasia: recent advances

CONTEXT

There have been 2 putative prostatic cancer precursors, prostatic intraepithelial neoplasia (PIN) and atypical adenomatous hyperplasia (adenosis), but PIN remains as a well-known precancerous condition.

OBJECTIVE

To describe recent advances in knowledge of PIN and to better define the diagnostic criteria and differential diagnosis of PIN.

DATA SOURCES

Review of the pertinent literature and our experience.

CONCLUSIONS

The presence of ductal/acinar epithelial changes including nuclear enlargement, prominent nucleoli, chromatin alterations, and luminal complexity is an easy way to identify the disorder. Four main patterns of high-grade PIN (HGPIN) have been described: tufting, micropapillary, cribriform, and flat. In addition, variants of HGPIN have also been described. Both HGPIN and prostatic carcinoma share an increased incidence and severity with advancing age and with high rates of occurrence in the peripheral zone of the prostate. Furthermore, HGPIN and prostate cancer share genetic and molecular markers as well, with PIN representing an intermediate stage between benign epithelium and invasive carcinoma. The clinical significance of HGPIN is that it identifies patients at risk for prostatic carcinoma. With the increased use of extended biopsy protocols, clinicians are more likely to identify HGPIN and less likely to miss concurrent carcinoma.

α-Methylacyl-CoA-Racemase Expression in Adenocarcinoma, Dysplasia and Non-Neoplastic Epithelium of the Stomach

Alpha-methylacyl-CoA-racemase (AMACR) is an essential enzyme in the oxidation of bile acid intermediates and branched-chain fatty acids. This study aims to examine the expression pattern, as well as diagnostic and prognostic significance, of AMACR in carcinoma, dysplasia and non-neoplastic epithelium of the stomach. A total of 158 cases, including 66 cases of gastric carcinoma (GC), 48 cases of dysplasia and 44 cases of non-neoplastic gastric mucosa, were examined by immunohistochemistry for AMACR. AMACR expression was divided into two categories: negative (negative-weak staining intensity) and positive (moderate-strong staining intensity). AMACR immunoreactivity was detected in only 2 of 44 (4.5%) cases of non-neoplastic epithelium. A significantly high frequency of AMACR expression was found in 40 of 48 (83.3%) cases of dysplasia and 34 of 66 (51.5%) carcinoma cases compared with cases of non-neoplastic epithelium (p < 0.05). The frequency of AMACR expression was significantly higher in dysplasia than in carcinoma cases (p < 0.05). AMACR expression was higher in intestinal- than diffuse-type GC (p < 0.05). In conclusion, this study suggests that AMACR immunostaining aids in distinguishing malignant or precancerous lesions from reactive epithelial atypia in gastric biopsy specimens. It also suggests that AMACR expression is more likely to be associated with intestinal-type adenocarcinoma in gastric carcinogenesis.

Diagnosis of adenocarcinoma in prostate needle biopsy tissue

Prostate cancer is a major public health problem throughout the developed world. For patients with clinically localised prostate cancer, the diagnosis is typically established by histopathological examination of prostate needle biopsy samples. Major and minor criteria are used to establish the diagnosis, based on the microscopic appearance of slides stained using haematoxylin and eosin. Major criteria include an infiltrative glandular growth pattern, an absence of basal cells and nuclear atypia in the form of nucleomegaly and nucleolomegaly. In difficult cases, basal cell absence may be confirmed by immunohistochemical stains for high-molecular-weight cytokeratins (marked with antibody 34betaE12) or p63, which are basal cell markers. Minor criteria include intraluminal wispy blue mucin, pink amorphous secretions, mitotic figures, intraluminal crystalloids, adjacent high-grade prostatic intraepithelial neoplasia, amphophilic cytoplasm and nuclear hyperchromasia. Another useful diagnostic marker detectable by immunohistochemistry is alpha-methylacyl coenzyme A racemase (AMACR), an enzyme selectively expressed in neoplastic glandular epithelium. Cocktails of antibodies directed against basal cell markers and AMACR are particularly useful in evaluating small foci of atypical glands, and in substantiating a diagnosis of a minimal adenocarcinoma. Reporting of adenocarcinoma in needle biopsy specimens should always include the Gleason grade and measures of tumour extent in the needle core tissue. Measures of tumour extent are (1) number of cores positive for cancer in the number of cores examined, (2) percentage of needle core tissue affected by carcinoma and (3) linear millimetres of carcinoma present.

α-methylacyl-CoA racemase (P504S)/34βE12/p63 triple cocktail stain in prostatic adenocarcinoma after hormonal therapy

Alpha-methylacyl-CoA racemase (AMACR) has recently been shown to be a highly sensitive marker for the diagnosis of prostate cancer. However, there is limited information concerning its utility as a marker for prostate carcinoma after hormonal therapy. Our current investigation was conducted to evaluate the expression of AMACR in patients with prostate carcinoma after hormonal therapy and assess its diagnostic utility in combination with p63 and high molecular weight cytokeratin (34betaE12) staining. Prostate tissues from 49 patients who had been treated with hormonal therapy were immunohistochemically analyzed for AMACR, 34betaE12, and p63 expression by a triple antibody cocktail stain. The staining intensities and the percentages of positively staining tumor cells were recorded. The correlations between AMACR expression and metastatic status, associated hormonal therapy regimens, and the extent of hormone therapy effect were analyzed. All malignant acini were completely negative for both basal cell markers (34betaE12 and p63). Tumor cells failed to demonstrate expression of AMACR in 14 (29%) of 49 cases. In the remaining 35 cases (71%), positive immunostaining for AMACR was noted, but with variable intensities and percentages of cells stained. Positive staining for AMACR in benign glands was not seen in any case. In all cases, basal cells were strongly stained by p63 in benign acini with a mean positive percentage of 96%. Similarly, basal cells in benign acini displayed moderate staining intensities for 34betaE12 in 3 (7%) of 41 cases and strong immunostaining for this marker in the remaining 38 cases (93%); the mean percentage of positive cells was 92%. alpha-methylacyl-CoA racemase expression may be substantially diminished or entirely lost in prostate carcinoma after hormonal therapy. This variation in AMACR expression does not correlate with the metastatic status, the modality of hormonal therapy, or the extent of therapy-related effect. It is important that pathologists be aware that some hormonally treated prostate carcinomas do not express AMACR, and that immunostaining in such cases must be interpreted with caution. A triple cocktail stain using AMACR, 34betaE12, and p63 can be helpful in evaluating prostate specimens for the presence of residual or recurrent carcinoma after hormonal therapy for cancer.

Microarrays as validation strategies in clinical samples: tissue and protein microarrays

The widespread use of DNA microarrays has led to the discovery of many genes whose expression profile may have significant clinical relevance. The translation of this data to the bedside requires that gene expression be validated as protein expression, and that annotated clinical samples be available for correlative and quantitative studies to assess clinical context and usefulness of putative biomarkers. We review two microarray platforms developed to facilitate the clinical validation of candidate biomarkers: tissue microarrays and reverse-phase protein microarrays. Tissue microarrays are arrays of core biopsies obtained from paraffin-embedded tissues, which can be assayed for histologically-specific protein expression by immunohistochemistry. Reverse-phase protein microarrays consist of arrays of cell lysates or, more recently, plasma or serum samples, which can be assayed for protein quantity and for the presence of post-translational modifications such as phosphorylation. Although these platforms are limited by the availability of validated antibodies, both enable the preservation of precious clinical samples as well as experimental standardization in a high-throughput manner proper to microarray technologies. While tissue microarrays are rapidly becoming a mainstay of translational research, reverse-phase protein microarrays require further technical refinements and validation prior to their widespread adoption by research laboratories.

Alpha-methylacyl coenzyme A racemase immunoreactivity in partial atrophy of the prostate

It was reported that 15 of 19 consultation cases of prostatic partial atrophy were a-methylacyl coenzyme A racemase (AMACR)-positive. We investigated partial atrophy cases from a single institution using a standard AMACR immunostaining method. Immunohistochemical analysis was performed using an antibody cocktail containing p63, high-molecular-weight keratin (34bE12), and AMACR antibodies on 122 foci of partial atrophy. AMACR staining was analyzed in partial atrophy (n = 122) and compared with adjacent benign glands (n = 122) and prostatic carcinomas (n = 28). Of 122 foci of partial atrophy, 38 (31.1%) showed AMACR immunoreactivity. Typically, AMACR staining was weak or moderate. In addition, 82 (67.2%) showed patchy to negative distribution of basal cells. Partial atrophy may show AMACR immunoreactivity when using a 34bE12, p63, and AMACR antibody cocktail staining method. Compounding this problem, focal lack of basal cells may be seen. However, the AMACR staining pattern of partial atrophy is usually comparable to that of adjacent benign glands and substantially different from adenocarcinoma.

What's new in prostate cancer disease assessment in 2006?

PURPOSE OF REVIEW

Issues relating to the disease are critical in the diagnosis, management, and prognostication of prostate cancer.

RECENT FINDINGS

New data have emerged regarding the disease of prostate cancer and its precursors. The diagnosis of prostate cancer on needle biopsy has been refined because of the recent discovery of alpha-methylacyl-CoA racemase, which preferentially labels adenocarcinoma of the prostate. Modifications and additions to the Gleason grading system were published based on a consensus conference of urological pathologists. Various models have been proposed using Gleason score, clinical findings, as well as measurements of tumor volume on needle biopsy to enhance the prediction in men undergoing radical prostatectomy and to predict "insignificance". Several studies have confirmed that certain findings in radical prostatectomy are adverse, yet conflicting studies were published as to the independent prognosis of tumor volume. The risk of cancer following a diagnosis of high-grade prostatic intraepithelial neoplasia on needle biopsy has decreased to the point at which this author does not recommend a routine repeat needle biopsy within the first year following the diagnosis of high-grade prostatic intraepithelial neoplasia.

SUMMARY

This review summarizes developments over the last year in the disease of prostate cancer and its precursors.

Kinetic fluorescence reverse transcriptase-polymerase chain reaction for alpha-methylacyl CoA racemase distinguishes prostate cancer from benign lesions

BACKGROUND

High-throughput gene expression profiling has recently shown that the mRNA for alpha-methylacyl CoA racemase (AMACR or P504S) is overexpressed in prostate carcinomas (PCa). Several immunohistochemical studies have reported the usefulness of anti-AMACR/P504S for detecting prostate cancer over the full range of prostate specimens encountered in surgical pathology. We tested real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for specific and sensitive detection of AMACR transcripts as a supplementary measure for discriminating between malignant and benign lesions in prostatic tissues.

METHODS

Total RNA was isolated from snap-frozen chips in 55 cases of benign prostatic hyperplasia (BPH) and from frozen sections in 57 prostatectomy cases. The latter were analyzed by an uropathologist (J.K.) and found to contain at least 50% malignant epithelia. Relative quantification of AMACR transcripts was performed by RT-PCR using hybridization probes for detection and PBGD for normalization.

RESULTS

Normalized AMACR transcript levels showed an average 3.75-fold increase in 57 prostate carcinomas cases when compared to 55 cases of BPH (p<0.0001). A 85.6% specificity and 64.9% sensitivity can be achieved if the cutoff is set at 12.95. AMACR expression levels among PCa cases were not statistically associated with the tumor and lymph node stage, the grading, the surgical margins, the Gleason score or progression.

DISCUSSION

The present study demonstrates the usefulness of quantitative AMACR-mRNA transcript detection in prostatic tissues as an alternative to immunological staining techniques. Since the latter clearly predominate in the laboratory routine, PCR-based detection of AMACR has the potential to gain widespread acceptance as a suitable future tool for monitoring prostate cancer patients.

Expression of alpha-methylacyl-coenzyme A racemase in dysplastic Barrett's epithelium

Although identification of epithelial dysplasia in Barrett's esophagus (BE) is critically important because of a significant risk of progression to invasive adenocarcinoma, the diagnosis of dysplasia may be challenging. Among confounding factors are interobserver variability, tangential sectioning, and severe mucosal inflammation leading to architectural and cytologic atypia similar to that of dysplasia. alpha-methylacyl-coenzyme A racemase (AMACR) is an enzyme involved in beta-oxidation of branched fatty acids and an established marker of prostate cancer. It is expressed in colon adenomas and adenocarcinomas but not in normal colonic epithelium suggesting a role in development of gastrointestinal malignancies. We investigated whether expression of AMACR can be used to identify dysplasia of BE and to distinguish it from reactive atypia. Ninety-six routinely processed biopsy and/or resection specimens (23 negative for dysplasia; 19, low-grade dysplasia; 22, high-grade dysplasia; 16, reactive atypia; and 16, esophageal adenocarcinoma) were immunostained using a monoclonal anti-AMACR antibody p504S. AMACR staining was uniformly negative in the groups negative for dysplasia and with reactive atypia. Only 2 (11%) of 19 specimens with low-grade dysplasia showed positive immunostaning, compared with 14 (64%) of 22 in high-grade dysplasia group. Of 16 specimens, 12 (75%) showed positive staining for AMACR in the adenocarcinoma group. Our data suggest that AMACR immunoreactivity is moderately sensitive in identification of high-grade dysplasia in BE and is highly specific in distinguishing high-grade dysplasia from reactive atypia. Further validation and prospective studies are warranted.

Comparison of annexin II, p63 and alpha-methylacyl-CoA racemase immunoreactivity in prostatic tissue: a tissue microarray study

BACKGROUND

Current ancillary markers for diagnosis in prostate biopsies include p63 and alpha-methylacyl-CoA racemase (AMACR). Annexin II (ANXII), a calcium and phospholipid binding protein, is lost in prostate cancer.

AIMS

To investigate ANXII expression in order to assess its utility as a novel diagnostic marker in comparison to p63 and AMACR.

METHODS

Using immunohistochemistry on six tissue microarrays, ANXII, p63, and AMACR expression was analysed from 210 radical prostatectomy cases. Staining was evaluated in benign and atrophic glands, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostatic adenocarcinoma. Separate scores were given for ANXII, AMACR and p63 expression.

RESULTS

Diffuse cytoplasmic expression of ANXII correlated with p63 reactivity in basal cells. Benign glands were positive for ANXII in 286/292 cores (98%) and negative for AMACR in all 292 cores. HGPIN showed heterogeneous expression of AMACR and ANXII. A significantly larger proportion of HGPIN glands were correctly identified as ANXII negative than as positive for AMACR. ANXII loss in prostate cancer was found in 282/320 cores (88%) and correlated with positive AMACR expression (272/320 cores, 85%), which was not statistically significant. There was no statistically significant correlation between ANXII scores and the clinical parameters examined.

CONCLUSIONS

Immunohistochemical staining for ANXII is a consistent and reliable marker of prostatic neoplasia. The findings of this study suggest the potential utility of ANXII as a diagnostic aid in prostate cancer histopathology.

AMACR Immunostaining is Useful in Detecting Dysplastic Epithelium in Barrett's Esophagus, Ulcerative Colitis, and Crohn's Disease

Alpha-methylacyl-CoA racemase (AMACR) catalyzes the racemization of alpha-methyl, branched carboxylic coenzyme A thioesters, and is overexpressed in a variety of neoplasms, such as prostate and colon cancer. The aim of this study was to evaluate AMACR expression in the metaplasia-dysplasia-carcinoma sequence in Barrett's esophagus (BE), ulcerative colitis (UC), and Crohn's disease (CD) and to determine whether its expression can be used to detect dysplastic epithelium in these conditions. One hundred thirty-four routinely processed biopsy and/or resection specimens from 134 patients with BE [M/F ratio: 5.7, mean age: 67 y (36 negative (intestinal metaplasia only), 14 indefinite for dysplasia (IND), 16 low-grade dysplasia (LGD), 32 high-grade dysplasia (HGD), and 36 invasive adenocarcinoma (ACA)] and 74 specimens from 74 patients with inflammatory bowel disease (IBD) [56 with ulcerative colitis, 18 with Crohn's disease, M/F ratio: 1.8, mean age: 55 y (17 negative, 7 IND, 26 LGD, 10 HGD, and 14 ACA)] were immunostained with a monoclonal AMACR antibody (p504S). The degree of cytoplasmic staining in all cases was evaluated in a blinded fashion according to the following grading system: 0, negative (0% cells positive); 1+, 1% to 10% cells positive; 2+, 10% to 50% cells positive; or 3+, >50% cells positive. In patients with BE, AMACR was not expressed in any negative foci (0%) but was significantly increased (P<0.0001) in foci of LGD (38%), HGD (81%), and ACA (72%). Three of 14 (21%) IND foci from 3 BE patients were only focally positive (grade 1: 7%, 2: 14%). However, 1 of these 3 patients had follow-up information available and had developed ACA subsequently. Similarly, in patients with IBD, AMACR was not expressed in any foci considered negative for dysplasia, but was significantly increased (P<0.0001) in foci of LGD (96%), HGD (80%), and ACA (71%). Only 1/7 (14%) IND focus from 1 patient was focally positive (grade 1). The sensitivity for the detection of LGD and HGD in BE and IBD was 38% and 81%, and 96% and 80%, respectively, for the 2 types of disorders. The specificity was 100% for both BE and IBD. AMACR is involved in the neoplastic progression in BE and IBD. The high degree of specificity of AMACR for dysplasia/carcinoma in BE and IBD suggests that it may be useful to detect neoplastic epithelium in these conditions.

Diagnostic utility of a p63/alpha-methyl coenzyme A racemase (p504s) cocktail in ambiguous lesions of the prostate upon needle biopsy

OBJECTIVE

To investigate the potential utility of a new combined immunostaining technique for diagnosing prostate cancer from histological analysis of needle biopsy specimens.

MATERIALS AND METHODS

Tissue was immunostained with a combination of antibodies against a basal cell marker (p63), and an enzyme commonly overexpressed in prostate cancer (p504s), on 63 small prostate cancer foci (<1 mm) and 109 cases of ambiguous lesions observed in needle biopsies.

RESULTS

After p63/p504s immunostaining, 93% of the ambiguous lesions (102/109) were classified. The final diagnoses retained were: 92 prostate cancers, seven atypical small acinar proliferations suspected of being malignant but undiagnosed, 21 prostatic intraepithelial neoplasia, five atypical adenomatous hyperplasia, and 36 atrophic benign mimickers of cancer.

CONCLUSIONS

Combining p504s as a positive marker for prostate cancer and p63 as a negative marker might improve diagnostic performance, sensitivity and specificity, and lead to fewer false-negative results. This simple immunostaining procedure should reduce the percentage of residual ambiguous lesions and the need for additional biopsies.

Prostate needle biopsies containing prostatic intraepithelial neoplasia or atypical foci suspicious for carcinoma: implications for patient care

PURPOSE

We identified information critical for patient treatment on prostate needle biopsies diagnosed with prostatic intraepithelial neoplasia or atypical foci suspicious for carcinoma.

MATERIALS AND METHODS

A search was performed using the MEDLINE database and referenced lists of relevant studies to obtain articles addressing the significance of finding PIN or atypical foci suspicious for carcinoma on needle biopsy.

RESULTS

There were certain results concerning PIN. 1) Low grade PIN should not be documented in pathology reports due to poor interobserver reproducibility and a relatively low risk of cancer following re-biopsy. 2) The expected incidence of HGPIN on needle biopsy is between 5% and 8%. 3) Although the diagnosis of HGPIN is subjective, interobserver reproducibility for its diagnosis is fairly high among urological pathologists, and yet only moderate among pathologists without special expertise in prostate pathology. 4) The median risk recorded in the literature for cancer following the diagnosis of HGPIN on needle biopsy is 24.1%, which is not much higher than the risk reported in the literature for repeat biopsy following a benign diagnosis. 5) The majority of publications that compared the risk of cancer in the same study following a needle biopsy diagnosis of HGPIN to the risk of cancer following a benign diagnosis on needle biopsy show no differences between the 2 groups. 6) Clinical and pathological parameters do not help stratify which men with HGPIN are at increased risk for a cancer diagnosis. 7) A major factor contributing to the decreased incidence of cancer following a diagnosis of HGPIN on needle biopsy in the contemporary era is related to increased needle biopsy core sampling, which detects many associated cancers on initial biopsy, such that re-biopsy, even with good sampling, does not detect many additional cancers. 8) It is recommended that men do not need routine repeat needle biopsy within the first year following the diagnosis of HGPIN, while further studies are needed to confirm whether routine repeat biopsies should be performed several years following a HGPIN diagnosis on needle biopsy. There were certain results concerning atypical glands suspicious for carcinoma. 1) An average of 5% of needle biopsy pathology reports are diagnosed as atypical glands suspicious for carcinoma. 2) Cases diagnosed as atypical have the highest likelihood of being changed upon expert review and urologists should consider sending such cases for consultation in an attempt to resolve the diagnosis as definitively benign or malignant before subjecting the patient to repeat biopsy. 3) Ancillary techniques using basal cell markers and AMACR (alpha-methyl-acyl-coenzyme A racemase) can decrease the number of atypical diagnoses, and yet one must use these techniques with caution since there are numerous false-positive and false-negative results. 4) The average risk of cancer following an atypical diagnosis is approximately 40%. 5) Clinical and pathological parameters do not help predict which men with an atypical diagnosis have cancer on repeat biopsy. 6) Repeat biopsy should include increased sampling of the initial atypical site, and adjacent ipsilateral and contralateral sites with routine sampling of all sextant sites. Therefore, it is critical for urologists to submit needle biopsy specimens in a manner in which the sextant location of each core can be determined. 7) All men with an atypical diagnosis need re-biopsy within 3 to 6 months.

CONCLUSIONS

It is critical for urologists to distinguish between a diagnosis of HGPIN and that of atypical foci suspicious for cancer on needle biopsy. These 2 entities indicate different risks of carcinoma on re-biopsy and different recommendations for followup.

The significance of the P504S expression pattern of high-grade prostatic intraepithelial neoplasia (HGPIN) with and without adenocarcinoma of the prostate in biopsy and radical prostatectomy specimens

Diagnosis of prostatic adenocarcinoma is usually not difficult in biopsy specimens. Problems may occur in biopsy specimens, containing only a few suspicious lesions. Recently, P504S has been tested as a new marker for prostatic carcinoma. When over-expressed in atypical glands without basal cells, it establishes the diagnosis of prostatic carcinoma. We analysed the staining intensity of P504S in 208 biopsy specimens from prostates (1) with adenocarcinoma (n=132), (2) with high-grade prostatic intraepithelial neoplasia (HGPIN) with adenocarcinoma (n=36), (3) with HGPIN alone (n=40) and in radical prostatectomy specimens with HGPIN adjacent to (n=54) or distant from adenocarcinoma (n=64). P504S expression was negative to weakly positive in biopsy specimens showing HGPIN without carcinoma and weakly positive in radical prostatectomy specimens revealing HGPIN distant from adenocarcinoma. In biopsy specimens with a combination of HGPIN and adenocarcinoma and in radical prostatectomy specimens with HGPIN adjacent to adenocarcinoma, P504S was strongly expressed. The same findings were made in radical prostatectomy specimens containing adenocarcinoma and HGPIN adjacent to or distant from adenocarcinoma and in preoperative biopsies revealing adenocarcinoma and HGPIN. These results suggest that moderate to strong P504S expression in HGPIN of biopsy specimens is indicative of an associated adenocarcinoma and may be helpful in the choice of therapy.