Is low-grade prostatic intraepithelial neoplasia a risk factor for cancer?

Oncogenic gene fusions in nonneoplastic precursors as evidence that bacterial infection can initiate prostate cancer

Prostate adenocarcinoma is the second most commonly diagnosed cancer in men worldwide, and the initiating factors are unknown. Oncogenic TMPRSS2:ERG (ERG+) gene fusions are facilitated by DNA breaks and occur in up to 50% of prostate cancers. Infection-driven inflammation is implicated in the formation of ERG+ fusions, and we hypothesized that these fusions initiate in early inflammation-associated prostate cancer precursor lesions, such as proliferative inflammatory atrophy (PIA), prior to cancer development. We investigated whether bacterial prostatitis is associated with ERG+ precancerous lesions in unique cases with active bacterial infections at the time of radical prostatectomy. We identified a high frequency of ERG+ non-neoplastic-appearing glands in these cases, including ERG+ PIA transitioning to early invasive cancer. These lesions were positive for ERG protein by immunohistochemistry and ERG messenger RNA by in situ hybridization. We additionally verified TMPRSS2:ERG genomic rearrangements in precursor lesions using tricolor fluorescence in situ hybridization. Identification of rearrangement patterns combined with whole-prostate mapping in three dimensions confirmed multiple (up to eight) distinct ERG+ precancerous lesions in infected cases. We further identified the pathogen-derived genotoxin colibactin as a potential source of DNA breaks in clinical cases as well as cultured prostate cells. Overall, we provide evidence that bacterial infections can initiate driver gene alterations in prostate cancer. In addition, our observations indicate that infection-induced ERG+ fusions are an early alteration in the carcinogenic process and that PIA may serve as a direct precursor to prostate cancer.

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

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

Managing high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical glands on prostate biopsy

Prostate biopsy is the gold standard for diagnosing prostate cancer and reliable pathological assessment is essential for guiding management. Research efforts over the past few years have aimed to establish a more universal approach to management according to pathological grading; however, high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical glands suspicious for carcinoma are two diagnoses without standardized follow-up and treatment pathways. Much of this uncertainty is due to limited evidence describing the subsequent rates of cancer and high-grade cancer when HGPIN or atypical glands are detected on initial biopsy. Fortunately, data from the past decade have shed light on these phenomena, and an improved understanding of the implications of the presence of HGPIN and atypical glands on prostate biopsy means that clinical recommendations can be made for the management of patients with these diagnoses.

Histopathological spectrum of 364 prostatic specimens including immunohistochemistry with special reference to grey zone lesions

Purpose:

Prostatic lesions on routine staining sometimes cause a diagnostic dilemma, especially when malignant tissue is limited and is mixed with benign prostatic glands or because of the presence of benign mimickers of carcinoma. The application of immunohistochemistry contributes a valuable differential diagnosis. This study aimed to evaluate a complete spectrum of various prostatic lesions and to supplement the histopathological diagnosis with immunohistochemistry in suspicious or atypical cases.

Methods:

A total of 364 consecutive prostatic specimens were evaluated. Routine hematoxylin and eosin staining and immunohistochemical staining against 34βE12 cytokeratin and proliferative marker (alpha-methylacyl-CoA-racemase, AMACR) were performed by use of the peroxidase antiperoxidase method.

Results:

Benign prostatic hyperplasia was the most frequent finding and involved 285 patients (78.3%). Prostatitis (majority nonspecific) formed the predominant subgroup in nonneoplastic lesions (n=119, 32.7%). The incidence of carcinoma was low (n=73, 20.1%). Of the 26 atypical or suspicious cases, 18 cases were positive for high molecular weight cytokeratin (high molecular weight cytokeratin, HMWCK) only, 4 cases were positive for AMACR only, and 4 cases showed positivity for both HMWCK and AMACR.

Conclusions:

Biopsy remains the gold standard. However, as an adjunct to biopsy, proliferative markers and basal cell markers have value for resolving suspicious or atypical cases.

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.

Primary cilia are lost in preinvasive and invasive prostate cancer

Prostate cancer is the second most commonly diagnosed cancer in men worldwide. Little is known about the role of primary cilia in preinvasive and invasive prostate cancer. However, reduced cilia expression has been observed in human cancers including pancreatic cancer, renal cell carcinoma, breast cancer, cholangiocarcinoma, and melanoma. The aim of this study was to characterize primary cilia expression in preinvasive and invasive human prostate cancer, and to investigate the correlation between primary cilia and the Wnt signaling pathway. Human prostate tissues representative of stages of prostate cancer formation (normal prostate, prostatic intraepithelial neoplasia (PIN), and invasive prostate cancer (including perineural invasion)) were stained for ciliary proteins. The frequency of primary cilia was determined. A decrease in the percentage of ciliated cells in PIN, invasive cancer and perineural invasion lesions was observed when compared to normal. Cilia lengths were also measured to indirectly test functionality. Cilia were shorter in PIN, cancer, and perineural invasion lesions, suggesting dysfunction. Primary cilia have been shown to suppress the Wnt pathway. Increased Wnt signaling has been implicated in prostate cancer. Therefore, we investigated a correlation between loss of primary cilia and increased Wnt signaling in normal prostate and in preinvasive and invasive prostate cancer. To investigate Wnt signaling in our cohort, serial tissue sections were stained for β-catenin as a measure of Wnt signaling. Nuclear β-catenin was analyzed and Wnt signaling was found to be higher in un-ciliated cells in the normal prostate, PIN, a subset of invasive cancers, and perineural invasion. Our results suggest that cilia normally function to suppress the Wnt signaling pathway in epithelial cells and that cilia loss may play a role in increased Wnt signaling in some prostate cancers. These results suggest that cilia are dysfunctional in human prostate cancer, and increase Wnt signaling occurs in a subset of cancers.

Tumor-infiltrating immune cells promoting tumor invasion and metastasis: existing theories

It is a commonly held belief that infiltration of immune cells into tumor tissues and direct physical contact between tumor cells and infiltrated immune cells is associated with physical destructions of the tumor cells, reduction of the tumor burden, and improved clinical prognosis. An increasing number of studies, however, have suggested that aberrant infiltration of immune cells into tumor or normal tissues may promote tumor progression, invasion, and metastasis. Neither the primary reason for these contradictory observations, nor the mechanism for the reported diverse impact of tumor-infiltrating immune cells has been elucidated, making it difficult to judge the clinical implications of infiltration of immune cells within tumor tissues. This mini-review presents several existing hypotheses and models that favor the promoting impact of tumor-infiltrating immune cells on tumor invasion and metastasis, and also analyzes their strength and weakness.

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.

Morphological transition of proliferative inflammatory atrophy to high-grade intraepithelial neoplasia and cancer in human prostate

BACKGROUND

Inflammation has been implicated as a potential etiological agent in human prostate cancer (PCa). Proliferative inflammatory atrophy (PIA) in prostate consists of areas of glandular atrophy associated with chronic inflammation and epithelial cell proliferation. It has been suggested that PIA is a candidate precursor of prostate malignancy. We aimed to explore the morphological transition between PIA and co-existing high-grade prostate intraepithelial neoplasia (HGPIN) and/or PCa.

METHODS

Serial slides of 50 whole-mounted radical prostatectomies were studied with H&E staining and immunostaining of cytokeratin 5 (CK5), glutathione S-transferase pi (GSTP1), hepatocyte growth factor receptor (c-MET), CCAAT/enhancer binding protein beta (C/EBPbeta), and Ki-67. Utilizing immunohistochemical stains to examine HGPIN, PIA-merging HGPIN, and PIA-merging PCa lesions, respectively.

RESULTS

A total of 1,188 HGPIN lesions were identified, of which 17% (198) were in the morphological process of merging with PIA. Thirty-six PIA-merging PCa lesions were also detected. The atrophic epithelial cells in such merging lesions had increased Ki-67 index and an intermediate phenotype: increased expression for CK5, GSTP1, c-MET, and C/EBPbeta. In addition, clusters of atypical epithelial cell hyperplasia, that is, with nuclear enlargement, hyperchromasia, and prominent nucleoli, were found in 16 PIA lesions. Such clusters of atypical cells that meet the criteria for HGPIN still expressed CK5 and were adjacent to focal chronic inflammation.

CONCLUSIONS

Direct morphological transition between PIA and HGPIN and/or PCa was present. The atrophic cells in these merging lesions had an intermediate phenotype. Clusters of atypical epithelial cell hyperplasia might represent the earliest transition from PIA to HGPIN. Prostate 69: 1378-1386, 2009. (c) 2009 Wiley-Liss, Inc.

Correlated alterations in prostate basal cell layer and basement membrane

Our recent studies revealed that focal basal cell layer disruption (FBCLD) induced auto-immunoreactions represented a contributing factor for human prostate tumor progression and invasion. As the basement membrane surrounds and attaches to the basal cell layer, our current study assessed whether FBCLD would impact the physical integrity of the associated basement membrane. Paraffin sections from 25-human prostate tumors were subjected to double immunohistochemistry to simultaneously elucidate the basal cell layer and the basement membrane with corresponding biomarkers. The physical integrity of the basement membrane overlying FBCLD was examined to determine the extent of correlated alterations. Of a total of 89 FBCLD encountered, 76 (85 %) showed correlated alterations in the overlying basement membrane, which included distinct focal disruptions or fragmentations. In the remaining 13 (15%) FBCLD, the overlying basement membrane showed significant attenuation or reduction of the immunostaining intensity. The basement membrane in all or nearly all ducts or acini with p63 positive basal cells was substantially thicker and more uniform than that in ducts or acini without p63 positive basal cells, and also, a vast majority of the focal disruptions occurred near basal cells that lack p63 expression. These findings suggest that focal disruptions in the basal cell layer and alterations in the basement membrane are correlated events and that the physical and functional status of the basal cells could significantly impact the physical integrity of the overlying basement membrane. As the degradation of both the basal cell layer and the basement membrane is a pre-requisite for prostate tumor invasion or progression, ducts or acini with focally disrupted basal cell layer and basement membrane are likely at greater risk to develop invasive lesions. Thus, further elucidation of the specific molecules and mechanism associated with these events may lead to the development of a more effective alternative for repeat biopsy to monitor tumor progression and invasion.

Precursor Lesions of Prostate Cancer

Several morphological lesions have been proposed that may act as potential precursor lesions of prostate cancer. These are the morphologically distinct entities of focal atrophy or post-atrophic hyperplasia (PAH), atypical adenomatous hyperplasia (AAH) or adenosis, and prostatic intraepithelial neoplasia (PIN). The diagnostic criteria of low-and high-grade PIN (LGPIN and HGPIN, respectively) and of lesions suspicious for cancer (LSC) have been established. In the present review, we present the current knowledge about the precursor lesions of prostate cancer. We focus on the epidemiology, pathogenesis, clinical markers, and differential diagnosis of PIN. The similarities between HGPIN and prostate cancer are also discussed. Furthermore, potential markers and management strategies (that is, repeat biopsy, chemoprevention, radical prostatectomy, radiotherapy) are outlined along with updated recommendations.

[Clinical significance of prostatic intraepithelial neoplasm and atypical small acinar proliferation: relationship with prostate cancer]

INTRODUCTION

Prostatic intraepithelial neoplasia (PIN) and atypical small acinar proliferation (ASAP) in the setting of prostatic needle biopsies are considered premalignant although questions still remain.

OBJECTIVES

In this paper, we have studied the clinical relevance of these histologic findings.

MATERIAL AND METHODS

We collected 138 subjects (108 PIN, 30 ASAP); in 67% we performed a second biopsy and the rate of cancer in this late biopsy were 19% and 27% respectively. We cannot identify any clinical factor to predict the finding of cancer in the re-biopsy (PSA, age, digital rectal examination, prostatic volume).

RESULTS

In the follow-up, we observed higher rates of cancer for the ASAP; the finding of ASAP was the single clinical or histopathological factor that was an independent predictor of cancer.

CONCLUSIONS

We observed that the finding of ASAP was an indication for re-biopsy because of the higher rates of cancer; on the contrary, the paper of PIN in the prostatic needle biopsy still requires further investigation.

Bad seeds produce bad crops: a single stage-process of prostate tumor invasion

It is a commonly held belief that prostate carcinogenesis is a multi-stage process and that tumor invasion is triggered by the overproduction of proteolytic enzymes. This belief is consistent with data from cell cultures and animal models, whereas is hard to interpret several critical facts, including the presence of cancer in "healthy" young men and cancer DNA phenotype in morphologically normal prostate tissues. These facts argue that alternative pathways may exist for prostate tumor invasion in some cases. Since degradation of the basal cell layer is the most distinct sign of invasion, our recent studies have attempted to identify pre-invasive lesions with focal basal cell layer alterations. Our studies revealed that about 30% of prostate cancer patients harbored normal appearing duct or acinar clusters with a high frequency of focal basal cell layer disruptions. These focally disrupted basal cell layers had significantly reduced cell proliferation and tumor suppressor expression, whereas significantly elevated degeneration, apoptosis, and infiltration of immunoreactive cells. In sharp contrast, associated epithelial cell had significantly elevated proliferation, expression of malignancy-signature markers, and physical continuity with invasive lesions. Based on these and other findings, we have proposed that these normal appearing duct or acinar clusters are derived from monoclonal proliferation of genetically damaged stem cells and could progress directly to invasion through two pathways: 1) clonal in situ transformation (CIST) and 2) multi-potential progenitor mediated "budding" (MPMB). These pathways may contribute to early onset of prostate cancer at young ages, and to clinically more aggressive prostate tumors.

Prostate cancer epigenetics: a review on gene regulation

Prostate cancer is the most common cancer in men in western countries, and its incidence is increasing steadily worldwide. Molecular changes including both genetic and epigenetic events underlying the development and progression of this disease are still not well understood. Epigenetic events are involved in gene regulation and occur through different mechanisms such as DNA methylation and histone modifications. Both DNA methylation and histone modifications affect gene regulation and play important roles either independently or by interaction in tumor initiation and progression. This review will discuss the genes associated with epigenetic alterations in prostate cancer progression: their regulation and importance as possible markers for the disease.

Prostate adenocarcinoma detected after high-grade prostatic intraepithelial neoplasia or atypical small acinar proliferation

OBJECTIVE

To review specific histological variables in patients with prostate cancer who previously had diagnoses of high-grade prostatic intraepithelial neoplasia (HGPIN) and/or atypical small acinar proliferation (ASAP), compared with those who had no such diagnoses.

PATIENTS AND METHODS

The histological characteristics of prostate cancers which were detected after a previous diagnosis of HGPIN and/or ASAP during 1998-2005 were investigated and correlated with the biopsies from patients with prostate cancer but with no such previous diagnoses.

RESULTS

HGPIN was followed by prostate cancer on repeat biopsy in 16.8% of patients, and ASAP in 26.7%. The mean age of patients with HGPIN or ASAP was higher than in those with no such diagnoses (P < 0.001). Similarly, patients with these previous diagnoses had a lower Gleason score (P = 0.017 and <0.001, respectively) and lower tumour volume variables (fewer tumour foci, P = 0.033 and 0.041, respectively) and shorter cancer (P = 0.048 and 0.030) in core biopsies than those without.

CONCLUSIONS

Patients with prostate cancer who had previous biopsies with HGPIN or ASAP were older and has lower grade- and volume-cancers than those who had not.

Effect of nutritional supplement challenge in patients with isolated high-grade prostatic intraepithelial neoplasia

OBJECTIVES

To investigate, through a prospective follow-up study, the effects of a dietary supplementation challenge in men with isolated high-grade prostatic intraepithelial neoplasia (HGPIN).

METHODS

The effects of a 6-month supplementation challenge with selenium, vitamin E, and soy isoflavonoids in men diagnosed with isolated HGPIN on biopsy were evaluated. A total of 100 patients entered the study. Of the 100 men, 29 were excluded because they refused additional biopsies or were noncompliant with the protocol, 71 underwent repeat biopsies at 3 months, and 58 underwent a third set at 6 months. The prostate-specific antigen (PSA) level was recorded at inclusion and before each set of biopsies. The study endpoint was defined as the diagnosis of PCa at 3 months or the histopathologic status at 6 months.

RESULTS

At the study endpoint, PCa had been found in 24 men (33.8%), HGPIN in 34 (47.9%), and no HGPIN or carcinoma in 13 (18.3%). The PCa risk throughout the study period was 25.0% in the group with a stable or decreasing PSA level (n = 48, 67.6%) and 52.2% in the group with an increasing PSA level (n = 23, 32.4%). This difference was statistically significant (P = 0.0458). Isolated HGPIN remaining at the first repeat biopsy and the percentage of initial cores with HGPIN were significant predictors of PCa at additional biopsies.

CONCLUSIONS

The results of our study have shown that a decrease in the PSA level while taking a selenium, vitamin E, and soy isoflavonoids supplement predicts for a significantly lower risk of PCa in future biopsies. The percentage of initial biopsy cores with HGPIN and isolated HGPIN remaining at the first repeat biopsy are significant predictors of PCa in future biopsies.

Focal degeneration of basal cells and the resultant auto-immunoreactions: a novel mechanism for prostate tumor progression and invasion

The development of human prostate cancer is believed to be a multistep process, progressing sequentially from normal, to hyperplasia, to prostatic intraepithelial neoplasia (PIN), and to invasive and metastatic lesions. High grade PIN has been generally considered as the direct precursor of invasive lesions, and the progression of PIN is believed to be triggered primarily, if not solely, by the overproduction of proteolytic enzymes predominately by cancer cells, which result in the degradation of the basement membrane. These theories, however, are hard to reconcile with two main facts: (1) only about 30% untreated PIN progress to invasive stage, while none of the current approaches could accurately identify the specific PIN or individuals at greater risk for progression, and (2) results from recent world-wide clinical trials with a wide variety of proteolytic enzyme inhibitors have been very disappointing, casting doubt on the validity of the proteolytic enzyme theory. Since over 90% of prostate cancer-related deaths result from invasion-related illness and the incidence of PIN could be up to 16.5-25% in routine or ultrasound guided prostate biopsy, there is an urgent need to uncover the intrinsic mechanism of prostate tumor invasion. Promoted by the facts that the basal cell population is the source of several tumor suppressors and the absence of the basal cell layer is the most distinct feature of invasive lesions, our recent studies have intended to identify the early alterations of basal cell layers and their impact on tumor invasion using multidisciplinary approaches. Our studies revealed that a subset of pre-invasive tumors contained focal disruptions (the absence of basal cells resulting in a gap greater than the combined size of at least three epithelial cells) in surrounding basal cell layers. Compared to their non-disrupted counterparts, focally disrupted basal cell layers had several unique features: (1) significantly lower proliferation; (2) significantly lower p63 expression; (3) significantly higher apoptosis; and (4) significantly higher leukocyte infiltration and stromal reactions. Compared to their counterparts distant from focal disruptions or overlying non-disrupted basal cell layers, epithelial cells overlying focal basal cell layer disruptions showed the following unique features: (1) significantly higher proliferation; (2) significantly higher expression of cell cycle control-, cell growth-, and stem cell-related genes; and (3) physical continuity with adjacent invasive lesions. Together, these findings suggest that focal basal cell layer disruptions could substantially impact the molecular profile and biological presentations of the overlying epithelial cells. Based on these and other findings, we have proposed that prostate tumor invasion is triggered by a localized degeneration of aged or injured basal cells and the resultant auto-immunoreactions. Our hypothesized steps for prostate tumor invasion include the following: (1) due to inherited or environmental factors, some patients contained cell cycle control- and renewal-related defects in the basal cell population that cause elevated basal cell degenerations; (2) the degradation products of degenerated basal cells or diffusible molecules of the overlying epithelial cells attract leukocyte infiltration; (3) leukocytes discharge their digestive enzymes upon the direct physical contact, resulting in a focal disruption in the basal cell layer, which leads to several focal alterations: (a) a focal loss of tumor suppressors and paracrine inhibitory function; (b) a focal increase of the permeability for growth-required nutrients and oxygen; (c) a focal increase of growth factors; (d) direct physical contact between epithelial and stromal cells; and (e) the exposure of the overlying epithelial cells directly to the stromal tissue fluid. These alterations individually or collectively stimulate or favor a clonal proliferation and stromal invasion of tumor progenitor or stem cells. Our hypothesis differs from the traditional theories in several aspects, including the triggering factor for the initiation of tumor invasion, the stage of tumor invasion, the cellular origin of invasive lesions, the significance of immunoreactive and stromal cells, and the potential approaches for early detection, treatment, and prevention of invasion. Our hypothesis represents a novel in vivo model as to the cellular mechanism leading to prostate tumor invasion. If confirmed, it could lead to a new direction to search for more effective approaches to combat prostate cancer. It could also have an immediate impact on patient care through improved pathologic evaluation of prostate tumor biopsies. More importantly, our hypothesis might be applicable, and significantly impact the detection, treatment, and prevention of other epithelium-derived tumors.

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.

High-grade prostatic intraepithelial neoplasia and atypical small acinar proliferation: predictive value for cancer in current practice

In earlier studies, prostate cancer (PCa) has been reported to appear in 21% to 48% of subsequent biopsies for isolated high-grade prostatic intraepithelial neoplasia (PIN) and in 34% to 60% for isolated atypical small acinar proliferation suspicious for, but not diagnostic of, malignancy (ASAP). We report results of follow-up biopsies in a recent cohort of community practice patients who underwent biopsy for PSA abnormalities. The study group consisted of 336 men with initial diagnoses of PIN (n = 204), ASAP (n = 78), or both lesions (n = 54) who underwent at least one repeat biopsy. Mean follow-up intervals in months were 6.0 for PIN, 3.8 for ASAP, and 4.9 for PIN/ASAP. Follow-up PCa detection rates were 23%, 37%, and 33%, respectively. The predictive value of ASAP was significantly higher than that for PIN (P = 0.0188). In 23 PIN studies with chronologic midpoints in the early 1990s, follow-up PCa was detected in a mean of 36% of cases, whereas this value was 21% after the year 2000. In 13 ASAP studies, mean PCa detection on follow-up was 45% until 1996 and 39% from 1997 to present. PIN/ASAP predicted PCa in 33% of cases in our study, similar to ASAP alone (P = 0.65) and had a mean predictive value of 44% in the literature. Factors that may account for the decline in PIN predictive values include: 1) extended biopsy techniques that yield higher rates of initial cancer detection, 2) lower detection rate for the remaining small cancers that may accompany PIN, and 3) remaining PIN cases may lack concomitant cancer.

Epigenetic changes in prostate cancer: implication for diagnosis and treatment

Prostate cancer is the most common noncutaneous malignancy and the second leading cause of cancer death among men in the United States. DNA methylation and histone modifications are important epigenetic mechanisms of gene regulation and play essential roles both independently and cooperatively in tumor initiation and progression. Aberrant epigenetic events such as DNA hypo- and hypermethylation and altered histone acetylation have both been observed in prostate cancer, in which they affect a large number of genes. Although the list of aberrantly epigenetically regulated genes continues to grow, only a few genes have, so far, given promising results as potential tumor biomarkers for early diagnosis and risk assessment of prostate cancer. Thus, large-scale screening of aberrant epigenetic events such as DNA hypermethylation is needed to identify prostate cancer-specific epigenetic fingerprints. The reversibility of epigenetic aberrations has made them attractive targets for cancer treatment with modulators that demethylate DNA and inhibit histone deacetylases, leading to reactivation of silenced genes. More studies into the mechanism and consequence of demethylation are required before the cancer epigenome can be safely manipulated with therapeutics as a treatment modality. In this review, we examine the current literature on epigenetic changes in prostate cancer and discuss the clinical potential of cancer epigenetics for the diagnosis and treatment of this disease.