The role of p53, bcl-2 and E-cadherin expression in predicting biochemical relapse for organ confined prostate cancer in Taiwan

Association of molecular biomarkers expression with biochemical recurrence in prostate cancer through tissue microarray immunostaining

The aim of the present study was to investigate the prognostic role of metallothionein-2A (MT-2A), E-cadherin, interleukin-6 (IL-6), cyclin-E, proliferating cell nuclear antigen (PCNA) and B cell lymphoma (Bcl)-2 in the biochemical recurrence of prostate cancer (PCa) using tissue microarray immunostaining. Tissue specimens from 128 PCa patients who underwent radical prostatectomy were processed and transferred onto tissue microarrays. The clinicopathological parameters of PCa patients were also recorded. Following immunohistochemical examination of MT-2A, E-cadherin, IL-6, cyclin-E, PCNA and Bcl-2 expression in PCa specimens, association analysis of biomarkers expression with the biochemical recurrence of PCa was performed. The results revealed that the overall rate of biochemical recurrence was 30.5% (39/128) and the median biochemical recurrence-free time was 19 months (range, 6–35 months). The biochemical recurrence rates in low-, intermediate- and high-risk PCa classification were 14.8 (8/54), 38.7 (24/62) and 58.3% (7/12), respectively. Survival analysis demonstrated that a decreased biochemical recurrence-free survival rate was noted in PCa cases with positive MT-2A and cyclin E expression as well as those with negative E-cadherin expression (P=0.022, 0.028 and 0.011, respectively). Subsequent multivariate Cox analysis revealed that MT-2A [hazard ratio (HR)=2.01; 95% confidence interval (CI)=1.08–3.15; P=0.005], E-cadherin (HR=1.79; 95% CI=1.08–2.21; P=0.042) and cyclin E (HR=1.92; 95% CI=1.22–2.45; P=0.020) were independent predictors of the biochemical recurrence of PCa. In conclusion, the present study provided clinical evidence that evaluation of molecular biomarkers expression may improve clinical prognostic accuracy for the biochemical recurrence of PCa. Of note, the expression of MT-2A, cyclin E and E-cadherin may serve as independent predictors for biochemical recurrence of PCa.

Multi-transcript profiling in archival diagnostic prostate cancer needle biopsies to evaluate biomarkers in non-surgically treated men

Background

Most biomarkers in prostate cancer have only been evaluated in surgical cohorts. The value of these biomarkers in a different therapy context remains unclear. Our objective was to test a panel of surgical biomarkers for prognostic value in men treated by external beam radiotherapy (EBRT) and primary androgen deprivation therapy (PADT).

Methods

The Fluidigm® PCR array was used for multi-transcript profiling of laser microdissected tumours from archival formalin-fixed diagnostic biopsies of patients treated by EBRT or PADT. Cases were matched for disease characteristics and had known 5 year biochemical relapse outcomes (n = 60). Results were validated by immunohistochemistry in a custom needle biopsy tissue microarray. Six biomarkers previously tested only in surgical cohorts were analysed (PTEN, E-Cadherin, EGFR, EZH2, PSMA, MSMB). Transcript and protein expression was correlated with clinical outcome analysed using Kruskal Wallis, Fisher’s test and Cox proportional hazard model.

Results

Altered expression of E-Cadherin (p = 0.008) was associated with early relapse after EBRT. In PADT treated men however only altered MSMB transcript was prognostic for early relapse (p = 0.001). The remaining biomarkers however did not demonstrate prognostic ability in either cohort. In a separate tissue array we validated altered E-Cadherin protein as a predictor of early relapse after EBRT (n = 47) (HR 0.34, CI p = 0.02) but not in PADT treated men (n = 63).

Conclusion

We demonstrate proof of principle of multiple transcript profiling in archival diagnostic biopsies of non-surgically treated men for biomarker discovery. We identify a role for E-Cadherin as a novel biomarker of early relapse following EBRT.

The role of treatment modality on the utility of predictive tissue biomarkers in clinical prostate cancer: a systematic review

BACKGROUND

Tissue biomarkers could pivotally improve clinical outcome prediction following prostate cancer therapy. Clinically, prostate cancer is managed by diverse treatment modalities whose individual influence on a biomarker's predictive ability is not well understood and poorly investigated in the literature.

OBJECTIVE

We conducted a systematic review to assess the predictive value of biomarkers in different treatment contexts in prostate cancer.

STUDY METHODOLOGY

A literature search was performed using the MeSH headings "prostate neoplasms" and "biological markers". Rigorous selection criteria identified studies correlating expression with clinical outcomes from primary androgen deprivation therapy (ADT), radical prostatectomy and radiotherapy (± neoadjuvant ADT).

STUDY RESULTS

Of 10,668 studies identified, 481 papers matched initial inclusion criteria. Following rescreening, 384 studies identified 236 individual tissue biomarkers, of which 29 were predictive on multivariate analysis in at least 2 independent cohorts. The majority were only tested in surgical cohorts. Only 8 predictive biomarkers were tested across all 3 treatments with Ki67 identified as universal predictive marker. p16 showed potential for treatment stratification between surgery and radiotherapy but needs further validation in independent studies.

CONCLUSIONS

Despite years of research, very few tissue biomarkers retain predictive value in independent validation across therapy context. Currently, none have conclusive ability to help treatment selection. Future biomarker research should consider the therapy context and use uniform methodology and evaluation criteria.

Tissue biomarkers for prostate cancer radiation therapy

Prostate cancer is the most common cancer and second leading cause of cancer deaths among men in the United States. Most men have localized disease diagnosed following an elevated serum prostate specific antigen test for cancer screening purposes. Standard treatment options consist of surgery or definitive radiation therapy directed by clinical factors that are organized into risk stratification groups. Current clinical risk stratification systems are still insufficient to differentiate lethal from indolent disease. Similarly, a subset of men in poor risk groups need to be identified for more aggressive treatment and enrollment into clinical trials. Furthermore, these clinical tools are very limited in revealing information about the biologic pathways driving these different disease phenotypes and do not offer insights for novel treatments which are needed in men with poor-risk disease. We believe molecular biomarkers may serve to bridge these inadequacies of traditional clinical factors opening the door for personalized treatment approaches that would allow tailoring of treatment options to maximize therapeutic outcome. We review the current state of prognostic and predictive tissue-based molecular biomarkers which can be used to direct localized prostate cancer treatment decisions, specifically those implicated with definitive and salvage radiation therapy.

[Prostate cancer: promising biomarkers related to aggressive disease]

BACKGROUND

Although a rapidly growing number of candidate biological markers of prognosis and/or response to specific treatments in prostate cancer, none have to date showed ability to completely prognosticate prostate cancer on evidence based urology.

OBJECTIVE

To review the pertinent literature on the issue.

ACQUISITION OF EVIDENCE

A comprehensive review of the current literature was done focusing on promising biomarkers related to aggressive prostate cancer.

SUMMARY OF EVIDENCE

Combined with the heterogeneous nature of the disease, mixed case series are the most common study design, impeding robust results and the development of an effective therapeutic strategy. Improvement in prostate cancer patient survival requires not only the identification of new therapeutic target based on detailed understanding of the biological mechanisms involved in metastatic dissemination and tumor growth but strong clinical studies as well.

CONCLUSION

Better study design involving potential markers and including well-classified and staged patients with robust methodology and adequate outcomes (mainly survival) are necessary to the field evolution.

Using molecular markers to help predict who will fail after radical prostatectomy

Recent phase III trial data clearly demonstrate that adjuvant therapy can reduce recurrence and increase survival after prostatectomy for prostate cancer. There is great interest in being able to accurately predict who is at risk of failure to avoid treating those who may not benefit. The standard markers consisting of prostate specific antigen (PSA), Gleason score, and pathological stage are not very specific, so there is an unmet need for other markers to aid in prognostic stratification. Numerous studies have been conducted with various markers and more recently gene signatures, but it is unclear whether any of them are really useful. We conducted a comprehensive review of the literature to determine the current status of molecular markers in predicting outcome after radical prostatectomy.

Bcl-2 as a predictive factor for biochemical recurrence after radical prostatectomy: an interim analysis

PURPOSE

The objective of this study was to determine Bcl-2 expression in localized prostate cancer and its potential role as a predictive factor for biochemical recurrence (BCR).

MATERIALS AND METHODS

This study included 171 Korean patients with newly diagnosed adenocarcinoma of the prostate who underwent radical prostatectomy (RP) without neoadjuvant therapy at a single center between February 2005 and May 2009. RP specimens obtained from these patients were analyzed for the expression of Bcl-2 using tissue microarray. The values of Bcl-2 and other clinicopathologic factors were evaluated. Statistical analysis was performed with contingency table analysis, chi-square tests, and a Cox proportional hazard model.

RESULTS

Bcl-2 expression was immunohistologically-confirmed in 42 patients (24.6%). Bcl-2 expression was not associated with conventional clinicopathologic factors. Bcl-2 negative patients had a significantly longer mean BCR-free survival than Bcl-2-positive patients (p=0.036). Among several variables, a high Gleason score in the RP specimen (≥8), extraprostatic extension, seminal vesicle invasion (SVI), lymphovascular invasion (LVI), and Bcl-2 expression were significant predictors of BCR based on univariate analysis. Multivariate Cox proportional hazards analysis revealed that BCR was significantly associated with a high prostate specific antigen level (p=0.047), SVI (p<0.001), a positive surgical margin (p=0.004) and Bcl-2 expression (p=0.012).

CONCLUSION

Bcl-2 expression in RP specimens is associated with a significantly worse outcome, suggesting a potential clinical role for Bcl-2. Post-operative Bcl-2 could be a significant predictor of outcome after RP.

E-cadherin and beta-catenin loss of expression related to bone metastasis in prostate cancer

OBJECTIVES

E-cadherin and beta-catenin are adhesion molecules responsible for the maintenance of normal epithelial cell phenotype. A disturbance in epithelial cell adhesion, which leads to a more invasive and metastatic phenotype, is a hallmark of tumor progression. Several immunohistochemical studies have reported a strong correlation between loss of their expression to higher stage and grade in prostate carcinoma, but their influence in metastatic process is not yet known. The aim of this study is to verify the role of adhesion molecules in the progression of prostate cancer (PC), assessing the expression of E-cadherin and beta-catenin in bone metastasis.

MATERIALS AND METHODS

Twenty-eight bone metastases of prostate carcinoma were submitted to immunohistochemistry analysis for E-cadherin and beta-catenin expression. In 6 patients, we were able to assess the expression of the adhesion molecules in the primary tumors and their respective metastases. The definition of normal expression for both antibodies was strong and diffuse expression in more than 70% of tumor cells.

RESULTS

In bone metastases, there was loss of expression of E-cadherin and beta-catenin in 86% and 82%, respectively. Among the primary tumors, E-cadherin and beta-catenin expression was normal in 83% and 50% cases, respectively. Considering the 6 patients with paired primary and bone metastasis, we found loss of expression for both E-cadherin and beta-catenin in most of the cases.

CONCLUSIONS

Comparing primary PC and its metastasis, we showed persistent loss of E-cadherin and beta-catenin expression. This phenomenon may be related to metastatic potential in PC, because we have shown underexpression for E-cadherin and beta-catenin in 86% and 82% of bone metastases.

Clinical outcome of Taiwanese men with clinically localized prostate cancer post-radical prostatectomy: a comparison with other ethnic groups

BACKGROUND

Prostate cancer incidence varies significantly among different ethnic groups. However, the report concerning the clinical outcome after radical prostatectomy (RP) in the low incidence Asian population is still limited. We aimed to compare the clinical outcome in patient treated with RP among different ethnic groups and to identify significant prognostic factors in Taiwanese patients.

METHODS

A total of 341 patients with clinical localized prostate cancer undergoing curative RP in three medical centers in Taiwan were included in this study. Ethnic group comparison was performed using the CaPSURE, SEARCH databases from United States (US) and one large European series. The Kaplan-Meier analysis and Cox proportional hazard model were used to identify significant predictors for prostate-specific antigen (PSA) recurrence.

RESULTS

Compared to the Caucasian white population in the US and Europe studies, the Taiwanese population have higher age at surgery and higher pre-operative PSA level. With mean and median follow-up of 39.1 months and 31.0 months (range 5-120 months), 127 men (37.2%) had PSA recurrence which was significant higher than the Western series. Significant predictors for PSA recurrence identified in the post-operative overall model were PSA level, pathological Gleason Score, pathological tumor stage and lymph node metastasis.

CONCLUSIONS

The clinical outcome of Taiwanese male with prostate cancer post-RP appears inferior to the Western country, which is largely due to delay surgery at higher PSA level. Earlier diagnosis and treatment may improve the cancer control of RP.

Biomolecular markers of outcome prediction in prostate cancer

Prostate cancer has a variable clinical outcome and, therefore, there is a clear need for novel molecular markers that are specifically associated with biologically aggressive disease to improve staging and prognostication and also to provide mechanistic information to facilitate treatment selection. Different candidate biomarkers have been identified that are linked to patient prognosis and/or response to specific treatments. Such molecules are involved in diverse cellular processes (including cell cycle regulation, cell death and apoptosis, signal transduction, cell adhesion, and angiogenesis) within which aberrant activity of several regulatory pathways has been seen in prostate cancer. Although the number of molecular markers continues to grow, mainly because of the advent of high-throughput methods, more work needs to be done to develop uniform standards for their characterization to enable comparison of markers across studies. Moreover, a rate-limiting step in the development of molecular markers is large-scale clinical assessment and their evaluation in the context of prediction model improvement. In fact, thus far, only a few studies have tested and demonstrated whether the addition of new biological markers improves the accuracy of standard clinical models (nomograms) in predicting biochemical progression in patients with clinically localized prostate cancer who underwent radical prostatectomy. Cancer 2009;115(13 suppl):3058-67. (c) 2009 American Cancer Society.

Utility of tissue microarrays for profiling prognostic biomarkers in clinically localized prostate cancer: the expression of BCL-2, E-cadherin, Ki-67 and p53 as predictors of biochemical failure after radical prostatectomy with nested control for clinical and pathological risk factors

A cure cannot be assured for all men with clinically localized prostate cancer undergoing radical treatment. Molecular markers would be invaluable if they could improve the prediction of occult metastatic disease. This study was carried out to investigate the expression of BCL-2, Ki-67, p53 and E-cadherin in radical prostatectomy specimens. We sought to assess their ability to predict early biochemical relapse in a specific therapeutic setting. Eighty-two patients comprising 41 case pairs were matched for pathological stage, Gleason grade and preoperative prostate-specific antigen (PSA) concentration. One patient in each pair had biochemical recurrence (defined as PSA >or= 0.2 ng mL(-1) within 2 years of surgery) and the other remained biochemically free of disease (defined as undetectable PSA at least 3 years after surgery). Immunohistochemical analysis was performed to assess marker expression on four replicate tissue microarrays constructed with benign and malignant tissue from each radical prostatectomy specimen. Ki-67, p53 and BCL-2, but not E-cadherin, were significantly upregulated in prostate adenocarcinoma compared with benign prostate tissue (P < 0.01). However, no significant differences in expression of any of the markers were observed when comparing patients who developed early biochemical relapse with patients who had no biochemical recurrence. This study showed that expression of p53, BCL-2 and Ki-67 was upregulated in clinically localized prostate cancer compared with benign prostate tissue, with no alteration in E-cadherin expression. Biomarker upregulation had no prognostic value for biochemical recurrence after radical prostatectomy, even after considering pathological stage, whole tumour Gleason grade and preoperative serum PSA level.

A switch from E-cadherin to N-cadherin expression indicates epithelial to mesenchymal transition and is of strong and independent importance for the progress of prostate cancer

PURPOSE

Cell adhesion molecules are of crucial importance in cancer invasion and metastasis. Epithelial to mesenchymal transition, characterized by reduced E-cadherin and increased N-cadherin expression, has been recognized as a feature of aggressive tumors, but the importance of this phenotype has not been settled in human prostate cancer. We here present novel data, with special focus on the independent relationship between an E-cadherin to N-cadherin switch (EN-switch) and patient prognosis.

EXPERIMENTAL DESIGN

Tissue microarray sections from a consecutive series of 104 radical prostatectomies during 1988 to 1994 with detailed clinicopathologic data and long follow-up were studied immunohistochemically for the expression of E-cadherin, N-cadherin, P-cadherin, beta-catenin, and p120(CTN).

RESULTS

Low E-cadherin expression was significantly associated with adverse clinicopathologic features, whereas other biomarkers were mostly related to Gleason score. In univariate survival analyses, cadherin switching (high N-cadherin and low E-cadherin) showed strong and significant associations with multiple end points of progression and cancer-specific death. Expression of the "basal cell marker" P-cadherin was associated with shorter time to skeletal metastasis (P = 0.036). In multivariate analysis of time to clinical recurrence, the "EN-switch" (hazard ratio, 4.3; P < 0.0005) had strong and independent prognostic effect, together with Gleason score.

CONCLUSION

These novel data unravel the importance of epithelial to mesenchymal transition for prostate cancer progression, and demonstration of a switch from E-cadherin to N-cadherin expression could have significant effect on the care of prostate cancer patients.

Sphingolipids and the sphingosine kinase inhibitor, SKI II, induce BCL-2-independent apoptosis in human prostatic adenocarcinoma cells

BACKGROUND

Elevated BCL-2 is one mechanism of therapeutic resistance in prostate cancer (PC), and new approaches are needed to overcome such resistance.

METHODS

We evaluated the effects of BCL-2 over-expression in human prostatic adenocarcinoma cells on their susceptibility to sphingolipids (SLs) and to the sphingosine kinase (SpK) inhibitor, SKI II.

RESULTS

In survival assays, no significant differences were observed in the responses to sphingosine or ceramide among parental PC-3 cells lacking detectable BCL-2 and BCL-2 over-expressing PC-3 transfectants; similarly, the responses to dimethyl-sphingosine (DMSP) of parental LNCaP cells and a BCL-2 over-expressing LNCaP transfectant were equivalent. SKI II induced protracted, BCL-2-independent survival loss in both PC-3 and LNCaP parental/transfectant pairs; in contrast, DMSP induced rapid cell shrinkage, caspase activation and caspase-dependent DNA fragmentation. DMSP-induced DNA fragmentation and loss of mitochondrial membrane potential were equivalent in BCL-2 transfectants and parental PC-3 cells and were not associated with BCL-2 downregulation. DMSP-mediated cytotoxicity was not associated with the enhanced production of reactive oxygen intermediates. SL analyses of parental and transfectant PC-3 cells did not reveal increased levels of sphingosine-1-phosphate in the BCL-2 transfectants; further, there only a modest early shift, corresponding to apoptotic onset, in pro- versus anti-apoptotic SLs in response to DMSP treatment.

CONCLUSIONS

Thus, in contrast to the inhibitory effects of BCL-2 on apoptosis induced by various agents in tumor cells, SKI II and selected pro-apoptotic SLs appear atypical in their independence from such inhibition, and may have merits as new candidates for treatment of AI PC.

Role of p21(WAF1) and p27(KIP1) in predicting biochemical recurrence for organ-confined prostate adenocarcinoma

BACKGROUND

Both p21(WAF1) and p27(KIP1) have been reported as prognostic markers predicting biochemical failure for prostate cancers. We examined the expression and prognostic significance of p21(WAF1) and p27(KIP1) in organ-confined (pT2) prostate cancer patients.

METHODS

The medical records of 53 pT2 prostate adenocarcinomas were analyzed retrospectively. Radical prostatectomy specimens were stained using anti-p21(WAF1) and anti-p27(KIP1) antibodies. Biochemical relapse was defined as 2 consecutive elevations in serum prostate specific antigen (PSA) level > 0.2 ng/mL with an interval of more than 3 months. The prognostic significance of p21(WAF1) and p27(KIP1) expression was assessed.

RESULTS

p21WAF1 immunoreactivity was found in 19 patients (35.8%). Twenty-nine tumors (54.7%) had decreased p27(KIP1) expression. Both markers were not associated with Gleason scores (p = 1.00 for both). At a median follow-up of 49 months, 15 patients (28.3%) experienced biochemical recurrence. Both p21 and p27 had no prognostic significance in log-rank test (p = 0.98 and p = 0.64, respectively).

CONCLUSION

p21(WAF1) and p27(KIP1) expression have no role in predicting biochemical relapse for stage pT2 prostate cancers.

E-Cadherin Protein Expression Predicts Prostate Cancer Salvage Radiotherapy Outcomes

PURPOSE

Radiotherapy for biochemical prostate cancer recurrence after prostatectomy achieves durable salvage rates of only 40% to 50%. Improved methods of identifying patients unlikely to benefit from salvage radiotherapy are needed. Altered expression of the adhesion molecule E-cadherin may be associated with the invasive and metastatic phenotype. We examined the relationship between E-cadherin expression and outcomes after salvage radiotherapy.

MATERIALS AND METHODS

E-cadherin expression was examined by immunohistochemistical analysis of a tissue microarray of prostatectomy tissues from patients who underwent salvage radiotherapy. The relation between E-cadherin staining, other risk factors and biochemical failure after salvage radiotherapy was analyzed using Kaplan-Meier and Cox regression methods.

RESULTS

Of 37 analyzable cases 25 showed aberrant E-cadherin expression, while the remainder had normal expression. At a median clinical followup of 40 months univariate analysis demonstrated that E-cadherin staining was not associated with Gleason score, extracapsular extension, surgical margin status, pre-prostatectomy or pre-radiotherapy prostate specific antigen, complete biochemical response after radiotherapy or adjunctive hormonal therapy but it was associated with seminal vesicle invasion. Two-year failure-free survival was 55% in patients with aberrant E-cadherin expression compared with 92% in patients with normal E-cadherin expression (p = 0.02). Multivariate analysis confirmed that aberrant E-cadherin expression was associated with salvage radiotherapy failure (p = 0.03).

CONCLUSIONS

Aberrant E-cadherin staining is associated with increased biochemical failure rates after salvage radiotherapy. Patients with biochemical failure after prostatectomy and aberrant E-cadherin expression are likely to have subclinical disseminated disease. Early systemic therapy may be warranted in these patients.

Molecular markers in the diagnosis of prostate cancer

The genetic alterations leading to prostate cancer are gradually being discovered. A wide variety of genes have been associated with prostate cancer development as well as tumor progression. Knowledge of gene polymorphisms associated with disease aid in the understanding of important pathways involved in this process and may result in the near future in clinical applications. Urinary molecular markers will soon be available to aid in the decision of repeat prostate biopsies. Recent findings suggest the importance of androgen signaling in disease development and progression. The further understanding of interaction of inflammation, diet, and genetic predisposition will improve risk stratification in the near future.

Aberrant expression of E-cadherin and beta-catenin in human prostate cancer

Cadherin-catenin complexes play a key role in embryonic development, and are associated with carcinogenesis and metastasis. We studied the expression of the major members of the family, including E-cadherin and beta-catenin in prostate cancer (PC), and correlated with Gleason grade and pathologic stage. Immunohistochemistry was performed on serial sections of paraffinized radical prostatectomy specimens to evaluate E-cadherin (n = 16) and beta-catenin (n = 17) expression using heat induced epitope retrieval. Benign appearing prostate epithelium was used as an internal control in each specimen. Two pathologists independently reviewed and scored the intensity and extent of immunostaining using a semiquantitative scale. The Mantel-Haenszel method, stratified by reviewer, was used to test for an association among Gleason score, pathologic stage, and the expression of E-cadherin or beta-catenin in PC. Gleason grade > or =7 cancers showed significantly lower expression of E-cadherin and beta-catenin compared to Gleason grade < 7 PC, P = 0.015 and 0.025, respectively. In addition, beta-catenin was down regulated in 4 of 5 (80%) specimens with identifiable high-grade prostatic intraepithelial neoplasia and had demonstrable nuclear staining in higher grade PC (P = 0.0001). However, E-cadherin and beta-catenin membranous or nuclear expressions were not significantly associated with final pathologic stage of the specimens (P values >0.05). Overall, the expression of E-cadherin and beta-catenin is significantly down regulated in PC compared to surrounding benign appearing prostate, which correlates with increasing Gleason grade. Furthermore, nuclear localization of beta-catenin in high grade PC may be a useful biomarker for aggressive PC.

N-cadherin switching occurs in high Gleason grade prostate cancer

BACKGROUND

The inappropriate expression of non-epithelial N-(neural) cadherin by epithelial cells, called cadherin switching, has been suggested to play a role in prostate cancer (PC) progression. We explored the role of N-cadherin as a biomarker in PC by correlating the expression with clinical parameters.

METHODS

Two pathologists blinded to patients' history independently reviewed and scored the intensity and extent of staining of N-cadherin expression in 44 randomly selected radical prostatectomy specimens. The expression was correlated with total Gleason grade, individual Gleason patterns, tumor stage, and preoperative serum prostate specific antigen (PSA) levels and P-values < 0.05 were considered statistically significant.

RESULTS

Of the 44 PC specimens, 14 (32%), 23 (52%), 7 (16%) consisted of Gleason grade 5-6, 7, and 8-10, respectively and 20/44 (45%) demonstrated N-cadherin expression. N-cadherin was expressed in 1/14 (7%) of Gleason 5-6 compared to 15/23 (65%) of Gleason grade 7, and 4/7 (57%) of Gleason grade 8-10, demonstrating a significant correlation between N-cadherin switching and higher Gleason grade (P = 0.001). While only about a third of primary or secondary Gleason pattern 3 demonstrated N-cadherin expression, a majority of Gleason patterns of > or = 4 expressed N-cadherin (P > 0.05), further suggesting that N-cadherin switching occurs with higher Gleason pattern. However, N-cadherin expression did not significantly correlate with preoperative serum PSA levels or tumor stage in our study cohort.

CONCLUSIONS

We have demonstrated for the first time that N-cadherin switching occurs in higher grade PC and correlates significantly with increasing Gleason patterns. N-cadherin may be as a useful biomarker of aggressive PC.

Molecular Markers and Prostate Cancer Prognosis

Prostate cancer is the most common malignancy among American men and is the second-leading cause of cancer-related mortality. Although radical prostatectomy and radiation therapy offer hope for cure for the majority of men with localized tumors, we continue to lack the tools to definitively determine which cancers need to be treated, which cancers will recur after treatment, and which cancers will behave aggressively when they have metastasized. Recent breakthroughs in molecular biology have led to the identification of a number of potential biomarkers for prostate cancer, many of which have been suggested to have prognostic significance. Eventually, combinations of these markers will hopefully enable us to more rationally facilitate counseling and direct management for men with prostate cancer.

E-cadherin expression in prostate adenocarcinomas in Chinese and its pathological correlates

INTRODUCTION

We examined the E-cadherin expression in prostate adenocarcinomas in Chinese to correlate this immunohistochemical marker with histopathological features.

MATERIALS AND METHODS

Primary adenocarcinomas from 122 radical prostatectomy specimens were stained using anti-E-cadherin (HECD-1) antibody. The association of E-cadherin expression with serum prostate-specific antigen (PSA), pathological stage and Gleason score was assessed by Kendall's tau-b test.

RESULTS

Aberrant E-cadherin expression was identified in 79 tumors (64.8%). Abnormal E-cadherin expression did not correlate to serum PSA (p = 0.802), tumor stage (p = 0.684) and Gleason score (p = 0.385).

CONCLUSIONS

The frequency of aberrant E-cadherin expression was higher in prostate adenocarcinomas of Chinese as compared to that reported in Caucasians. No association with pathological stage, Gleason score and serum PSA was identified.