TMPRSS2-ERG Gene Fusion and Clinicopathologic Characteristics of Korean Prostate Cancer Patients

Prevalence and clinical application of TMPRSS2-ERG fusion in Asian prostate cancer patients: a large-sample study in Chinese people and a systematic review

Fusion between the transmembrane protease serine 2 and v-ets erythroblastosis virus E26 oncogene homolog (TMPRSS2-ERG fusion) is a common genetic alteration in prostate cancer among Western populations and has been suggested as playing a role in tumorigenesis and progression of prostate cancer. However, the prevalence of TMPRSS2-ERG fusion differs among different ethnic groups, and contradictory results have been reported in Asian patients. We aim to evaluate the prevalence and significance of TMPRSS2-ERG fusion as a molecular subtyping and prognosis indicator of prostate cancer in Asians. We identified the fusion status in 669 samples from prostate biopsy and radical prostatectomy by fluorescence in situ hybridization and/or immunohistochemistry in China. We examined the association of TMPRSS2-ERG fusion with clinicopathological characteristics and biochemical recurrence by Chi-square test and Kaplan–Meier analysis. Finally, a systematic review was performed to investigate the positive rate of the fusion in Asian prostate cancer patients. McNemar's test was employed to compare the positive rates of TMPRSS2-ERG fusion detected using different methods. The positive rates of TMPRSS2-ERG fusion were 16% in our samples and 27% in Asian patients. In our samples, 9.4% and 19.3% of cases were recognized as fusion positive by fluorescence in situ hybridization and immunohistochemistry, respectively. No significant association between the fusion and clinical parameters was observed. TMPRSS2-ERG fusion is not a frequent genomic alteration among Asian prostate cancer patients and has limited significance in clinical practices in China. Besides ethnic difference, detection methods potentially influence the results showing a positive rate of TMPRSS2-ERG fusion.

Detection of tmprss2-erg and tmprss2-egr1 gene fusion in prostate cancer from a Chinese population

Background

TMPRSS2: ETS gene fusion occurs recurrently in a high proportion of prostate cancer (PCa) patients in Western countries. However, for Chinese PCa patients, no solid conclusion could be drawn from the present studies, as the results varied considerably between the limited reports.

Results

In this study, we evaluated the prevalence of such gene rearrangements in a small number of Chinese PCa patients and discovered that 6 out of 27 (22.2%) were found to harbor the TMPRSS2: ERG fusion, the ratio was much lower than that in Western countries. Furthermore, we first identified TMPRSS2: EGR1 gene fusion, suggesting other chromosome rearrangements besides ETS gene family harbor in prostate cancer. The hybrid transcript was predicted to encode a truncated EGR1 protein by ORF finder, which might play a key role in prostate cancer.

Conclusions

We reported that the total occurrence rate of TMPRSS2: ERG fusion gene in this small group of Chinese patients was lower than the reported frequencies in European descent patients but comparable to other reported frequencies in Asian populations. The occurrence of TMPRSS2: EGR1 gene fusion suggested other chromosome rearrangements in prostate cancer.

Survival outcomes of Asian younger men (< 55 years) undergoing radical prostatectomy: a review of prostate cancer database in a tertiary hospital in Singapore

PURPOSE

Prostate cancer largely affects older men. This study aims to investigate prostate cancer in younger men (< 55 years) to shed light on the survival outcomes of this unique subset of patients in Asian context.

METHODS

Data were obtained from the Singapore General Hospital Prostate Cancer Registry. Data on all men with clinically organ confined prostate cancer who underwent radical prostatectomy between 1998 and 2016 were obtained from the registry. Tumor characteristics, follow-up data, and cause of death were acquired.

RESULTS

A total of 1120 men underwent radical prostatectomy between 1998 and 2016. Of these, 12 were aged ≤ 44 years, 106 were aged 45-54 years, 596 were aged 55-64, 397 were aged 65-74 and 9 were aged ≥ 75. There was no difference across age groups when comparing Gleason ≤ 7 vs Gleason ≥ 8 disease, T1/2 vs T3/4 disease and the median PSA values were similar. No difference was observed in overall survival or prostate cancer specific survival among 4 age groups (≤ 44, 45-54, 55-64, 65-74) (p = 0.156 and p = 0.227 respectively). Although there was a trend of increasing rate of biochemical recurrence for older patients, it's not statistically significant (p = 0.157). Time to biochemical recurrence was similar as well (p = 0.257).

CONCLUSION

This large cohort of Asian patients who underwent radical prostatectomy did not show significant age-related differences in important parameters and outcomes.

The expression profile and heterogeneity analysis of ERG in 633 consecutive prostate cancers from a single center

BACKGROUND

Overexpression of ERG protein resulting from TMPRSS2:ERG rearrangement is highly specific for prostate cancer (PCa). However, the biological function of this fusion protein and its relationship with clinicopathological features still remain controversial.

METHOD

In this study, we evaluated ERG protein expression/gene rearrangement and heterogeneity by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in a cohort of 633 consecutive PCa initially diagnosed by core-needle biopsy in the West China Hospital.

RESULT

Overall, ERG protein expression was detected in 16.7% (106 of 633) cases, and frequently observed in PCa patients less than 60 years of age (31.9% vs 15.5%, P = 0.004) and in PCa with Gleason score less than 8 (20.0% vs 13.4%, P = 0.027), but infrequently observed in cases with intraductal carcinoma of the prostate (IDC-P) (10.0% vs 18.6%, P = 0.012). Follow-up analysis found that patients who progressed to castration-resistant prostate cancer (CRPC) have a lower frequency of ERG protein expression at initial biopsies compared to androgen deprivation therapy (ADT)-sensitive cases (14.1% vs 23.5%, P = 0.042), but Kaplan-Meier curve showed that ERG protein expression was not an independent prognostic marker. Of all the 106 ERG-positive cases, eight cases (7.5%) exhibited heterogeneous expression of ERG protein, in which ERG was only positive in tumors with Gleason pattern 3, but negative in Gleason pattern 4. The FISH analysis was consistent with IHC in six of these cases. In the other two cases, ERG rearrangement was detected in tumors with both Gleason pattern 3 and 4 by FISH, despite the negative protein expression in Gleason pattern 4. In case 1, a repeated biopsy was performed when the disease progressed to CRPC, and no ERG-positive cells were identified neither by IHC nor FISH.

CONCLUSION

This was by far the largest series of ERG expression and heterogeneity analysis in Chinese PCa. The ERG rearrangement seemed to be frequently expressed in patients with relatively younger age and lower Gleason score and infrequently expressed in PCa with the IDC-P. PCa with positive ERG were less frequently to progress to CRPC, but there was no prognostic significance of ERG expression. In heterogeneous cases, ERG protein was detectable only in tumors with Gleason pattern 3 but not in pattern 4. Tumor cells with positive ERG expression/rearrangement seemed easily response to ADT.

Characterize the difference between TMPRSS2-ERG and non-TMPRSS2-ERG fusion patients by clinical and biological characteristics in prostate cancer

The TMPRSS2-ERG gene fusion were frequently found in prostate cancer, and thought to play some fundamental mechanisms for the development of prostate cancer. However, until now, the clinical and prognostic significance of TMPRSS2-ERG gene fusion was not fully understood. In this study, based on the 281 prostate cancers that constructed from a historical watchful waiting cohort, the statistically significant associations between TMPRSS2-ERG gene fusion and clinicopathologic characteristics were identified. In addition, the Elastic Net algorithm was used to predict the patients with TMPRSS2-ERG fusion status, and good predictive results were obtained, indicating that this algorithm was suitable to this prediction problem. The differential gene network was constructed from the network, and the KEGG enrichment analysis demonstrated that the module genes were significantly enriched in several important pathways.

Predictive significance of TMRPSS2-ERG fusion in prostate cancer: a meta-analysis

Background

Prostate cancer is a major malignancy in males. TMPRSS2-ERG is a high-frequency fusion gene expressed in prostate cancer and plays a vital role in carcinogenesis. Recent studies showed that TMPRSS2-ERG is a potential predictive biomarker for prostate cancer. However, the predictive value of TMPRSS2-ERG fusion is yet unclear.

Methods

A total of 76 relevant articles, published from 2015 to 2017, were obtained from PubMed, Web of Science, EMBASE, Scopus, the Cochrane Library, and CNKI databases to investigate the predictive significance of TMPRSS2-ERG fusion in prostate cancer. Pooled odds ratio (ORs) with 95% confidence intervals (CIs) were calculated to estimate the correlation between TMPRSS2-ERG fusion gene and tumor features.

Results

The pooled or stratified analysis showed that the TMPRSS2-ERG fusion gene had a highly predictive potential. First, TMPRSS2-ERG fusion was associated with T-stage at diagnosis (T3–4 vs. T1–2 OR: 1.40; 95% CI 1.33–1.48) and metastasis (M1 vs. M0 OR: 1.35; 95% CI 1.02–1.78) but not with biochemical recurrence or prostate cancer-specific mortality. Furthermore, the subgroup analysis found that the TMPRSS2-ERG fusion gene was correlated with Gleason (G) scores, and the fusion was common in prostate cancer with G ≤ 7. Additionally, the meta-analysis demonstrated that the fusion was likely to occur in young patients (> 65 vs. ≤ 65 OR: 0.68; 95% CI 0.52–0.89), in patients with high PSA levels (> 10 vs. ≤ 10 OR: 1.30; 95% CI 1.21–1.38), and in patients with peripheral involvement (positive vs. negative OR: 1.17; 95% CI 1.08–1.28), while not associated with tumor volume. Finally, the subgroup analysis of different fusion types demonstrated that the deletion-type fusion was significantly associated with the malignant degree of prostate cancer (pooled OR: 5.67; 95% CI 2.85–11.28). Moreover, the deletion-type was common in Africa patients, followed by Caucasian patients, and no significant difference was observed in the incidence of different fusion types in the Asian population.

Conclusions

The meta-analysis findings suggested that the TMPRSS2-ERG fusion gene might be a predictive marker for prostate cancer patients, and might be valuable for assessing the characteristics of prostate cancer for individualized treatment and prognosis evaluation.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0672-2) contains supplementary material, which is available to authorized users.

Epidemiology of prostate cancer in Asian countries

The incidence of prostate cancer has been increasing worldwide in recent years. The GLOBOCAN project showed that prostate cancer was the second most frequently diagnosed cancer and the fifth leading cause of cancer mortality among men worldwide in 2012. This trend has been growing even in Asian countries, where the incidence had previously been low. However, the accuracy of data about incidence and mortality as a result of prostate cancer in some Asian countries is limited. The cause of this increasing trend is multifactorial. One possible explanation is changes in lifestyles due to more Westernized diets. The incidence is also statistically biased by the wide implementation of early detection systems and the accuracy of national cancer registration systems, which are still immature in most Asian countries. Mortality rate decreases in Australia, New Zealand and Japan since the 1990s are possibly due to the improvements in treatment and/or early detection efforts employed. However, this rate is increasing in the majority of other Asian countries. Studies of latent and incidental prostate cancer provide less biased information. The prevalence of latent and incidental prostate cancer in contemporary Japan and Korea is similar to those in Western countries, suggesting the influence of lifestyle changes on carcinogenesis. Many studies reported evidence of both congenital and acquired risk factors for carcinogenesis of prostate cancer. Recent changes in the acquired risk factors might be associated with the increasing occurrence of prostate cancer in Asian countries. This trend could continue, especially in developing Asian countries.

The androgen receptor malignancy shift in prostate cancer

BACKGROUND

Androgens and the androgen receptor (AR) are necessary for the development, function, and homeostatic growth regulation of the prostate gland. However, once prostate cells are transformed, the AR is necessary for the proliferation and survival of the malignant cells. This change in AR function appears to occur in nearly every prostate cancer. We have termed this the AR malignancy shift.

METHODS

In this review, we summarize the current knowledge of the AR malignancy shift, including the DNA-binding patterns that define the shift, the transcriptome changes associated with the shift, the putative drivers of the shift, and its clinical implications.

RESULTS

In benign prostate epithelial cells, the AR primarily binds consensus AR binding sites. In carcinoma cells, the AR cistrome is dramatically altered, as the AR associates with FOXA1 and HOXB13 motifs, among others. This shift leads to the transcription of genes associated with a malignant phenotype. In model systems, some mutations commonly found in localized prostate cancer can alter the AR cistrome, consistent with the AR malignancy shift. Current evidence suggests that the AR malignancy shift is necessary but not sufficient for transformation of prostate epithelial cells.

CONCLUSIONS

Reinterpretation of prostate cancer genomic classification systems in light of the AR malignancy shift may improve our ability to predict clinical outcomes and treat patients appropriately. Identifying and targeting the molecular factors that contribute to the AR malignancy shift is not trivial but by doing so, we may be able to develop new strategies for the treatment or prevention of prostate cancer.

Status of TMPRSS2-ERG fusion in prostate cancer patients from India: correlation with clinico-pathological details and TMPRSS2 Met160Val polymorphism

Background

Prostate cancer (PCa) shows considerable clinical heterogeneity that has been primarily attributed to variable molecular alterations. TMPRSS2-ERG fusion is one such molecular subtype that has been associated with predominantly poor prognosis. More recently, a single nucleotide polymorphism (SNP) in the TMPRSS2 gene rs12329760 C>T (Met160Val) has been shown to positively correlate with the fusion status and also to be associated with increased risk for PCa. The aim of the present study is to determine the frequency of TMPRSS2-ERG fusion and association of rs12329760 in Indian PCa patients with fusion status.

Methods

TMPRSS2-ERG fusion by fluorescence in situ hybridization was determined in 102 of 150 PCa biopsy-proven cases. Genotyping for rs12329760 was performed on the entire cohort of 150 cases by Sanger sequencing.

Results

TMPRSS2-ERG fusion was seen in 27 of 102 (26%) cases. Fusion-positive patterns in this study showed fusion by translocation in nine of 27 cases (33.5%), by deletion in six of 27 (22%) cases, and by insertion in 12 of 27 cases (44.5%). No association of the fusion status with Gleason Score, pattern, or perineural invasion was seen. The TMPRSS2 SNP rs12329760 'T' allele was prevalent with a frequency of 0.27 in the PCa patients. The SNP was significantly associated with fusion [odds ratio (OR) = 2.176, 95% confidence interval (CI) = 1.012-4.684, P = 0.04], more specifically fusion by deletion (P = 0.04).

Conclusion

The results provided here determine the frequency of TMPRSS2-ERG fusions (26%) in a fairly large cohort of Indian PCa cases and also the association of rs12329760 SNP with TMPRSS2-ERG fusion. No association with other clinico-pathological features was observed. Future studies with clinical outcomes are warranted in this population.

Mutation of MED12 is not a frequent occurrence in prostate cancer of Korean patients

Prostate cancer is one of the major health care problems, but the molecular pathogenesis has been relatively insufficiently elucidated. Recently, whole exome sequencing of prostate cancer identified recurrent mutations involving MED12 in Caucasian patients, which finding was not reproduced in one subsequent study by Sanger sequencing. Thus, we investigated mutation status of MED12 in exons 2 and 26 by Sanger sequencing in 102 radical prostatectomy cases from Korean patients. The analysis found the mutation in none of the cases. Therefore, MED12 mutation does not appear to represent a significant molecular alteration in this cohort of patients according to the analysis by the traditional “gold standard.”

Intrafocal heterogeneity of ERG protein expression and gene fusion pattern in prostate cancer

BACKGROUND

Prostate cancer is considered to be highly heterogeneous, with various morphologic features and biologic behaviors. The TMPRSS2-ERG gene fusion is the most frequently observed genetic aberration in prostate cancer. The aim of this study was to elucidate the intrafocal heterogeneity of ERG gene fusion status.

METHODS

ERG immunohistochemistry (IHC) was performed in samples from 168 prostate cancer patients who had undergone radical prostatectomy, and 40 cases showing ERG-positive IHC staining were selected for tissue microarray (TMA) construction. Two to six representative cores were selected from each tumor focus. In the cases with heterogeneous ERG IHC staining intensity, the areas showing different intensities were separately selected. Using the TMA blocks, IHC and fluorescence in situ hybridization (FISH) were conducted to evaluate the heterogeneity of ERG protein expression and ERG fusion gene patterns, respectively, in a single tumor focus. Heterogeneity of ERG IHC staining was defined as the simultaneous presence of negative and positive cores in the same tumor focus. Heterogeneity of ERG FISH was defined by the presence of cores with positive and negative FISH signals or cores with break-apart and interstitial deletion FISH signals in the same tumor focus.

RESULTS

A total of 202 TMA cores were isolated from 40 ERG-positive cases. Of the 202 total cores, 19 were negative for ERG IHC staining, and 46 showed 1+, 52 showed 2+, and 85 showed 3+ ERG staining intensity. Eleven cores were negative for ERG FISH signal, 119 cores showed ERG break-apart FISH signals, and the remaining 72 cores revealed interstitial deletion. Intrafocal heterogeneity of ERG IHC staining was found in 20% (8/40) of cases, and intrafocal heterogeneity of ERG gene fusion pattern was found in 32.5% (13/40) of cases.

CONCLUSIONS

In summary, this study showed significantly frequent intrafocal heterogeneity of ERG protein expression, gene fusion status and fusion pattern. This heterogeneity can be caused by the development of subclones during cancer progression or the intermingling of different tumors.

Whole-genome and Transcriptome Sequencing of Prostate Cancer Identify New Genetic Alterations Driving Disease Progression

BACKGROUND

Global disparities in prostate cancer (PCa) incidence highlight the urgent need to identify genomic abnormalities in prostate tumors in different ethnic populations including Asian men.

OBJECTIVE

To systematically explore the genomic complexity and define disease-driven genetic alterations in PCa.

DESIGN, SETTING, AND PARTICIPANTS

The study sequenced whole-genome and transcriptome of tumor-benign paired tissues from 65 treatment-naive Chinese PCa patients. Subsequent targeted deep sequencing of 293 PCa-relevant genes was performed in another cohort of 145 prostate tumors.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The genomic alteration landscape in PCa was analyzed using an integrated computational pipeline. Relationships with PCa progression and survival were analyzed using nonparametric test, log-rank, and multivariable Cox regression analyses.

RESULTS AND LIMITATIONS

We demonstrated an association of high frequency of CHD1 deletion with a low rate of TMPRSS2-ERG fusion and relatively high percentage of mutations in androgen receptor upstream activator genes in Chinese patients. We identified five putative clustered deleted tumor suppressor genes and provided experimental and clinical evidence that PCDH9, deleted/loss in approximately 23% of tumors, functions as a novel tumor suppressor gene with prognostic potential in PCa. Furthermore, axon guidance pathway genes were frequently deregulated, including gain/amplification of PLXNA1 gene in approximately 17% of tumors. Functional and clinical data analyses showed that increased expression of PLXNA1 promoted prostate tumor growth and independently predicted prostate tumor biochemical recurrence, metastasis, and poor survival in multi-institutional cohorts of patients with PCa. A limitation of this study is that other genetic alterations were not experimentally investigated.

CONCLUSIONS

There are shared and salient genetic characteristics of PCa in Chinese and Caucasian men. Novel genetic alterations in PCDH9 and PLXNA1 were associated with disease progression.

PATIENT SUMMARY

We reported the first large-scale and comprehensive genomic data of prostate cancer from Asian population. Identification of these genetic alterations may help advance prostate cancer diagnosis, prognosis, and treatment.

Diverse Immunoprofile of Ductal Adenocarcinoma of the Prostate with an Emphasis on the Prognostic Factors

BACKGROUND

Ductal adenocarcinoma (DAC) of the prostate is an uncommon histologic subtype whose prognostic factors and immunoprofile have not been fully defined.

METHODS

To define its prognostic factors and immunoprofile, the clinicopathological features, including biochemical recurrence (BCR), of 61 cases of DAC were analyzed. Immunohistochemistry was performed on tissue microarray constructs to assess the expression of prostate cancer-related and mammalian target of rapamycin (mTOR) signaling-related proteins.

RESULTS

During the median follow-up period of 19.3 months, BCR occurred in 26 cases (42.6%). DAC demonstrated a wide expression range of prostate cancer-related proteins, including nine cases (14.8%) that were totally negative for pan-cytokeratin (PanCK) immunostaining. The mTOR signaling-related proteins also showed diverse expression. On univariate analysis, BCR was associated with high preoperative serum levels of prostate-specific antigen (PSA), large tumor volume, predominant ductal component, high Gleason score (GS), comedo-necrosis, high tumor stage (pT), lymphovascular invasion, and positive surgical margin. High expressions of phospho-mTOR (p-mTOR) as well as low expressions of PSA, phospho-S6 ribosomal protein (pS6) and PanCK were associated with BCR. On multivariable analysis, GS, pT, and immunohistochemical expressions of PanCK and p-mTOR remained independent prognostic factors for BCR.

CONCLUSIONS

These results suggest GS, pT, and immunohistochemical expressions of PanCK and p-mTOR as independent prognostic factors for BCR in DAC. Since DAC showed diverse expression of prostate cancer-related proteins, this should be recognized in interpreting the immunoprofile of DAC. The diverse expression of mTOR-related proteins implicates their potential utility as predictive markers for mTOR targeted therapy.

Prostate cancer in Jordanian-Arab population: ERG status and relationship with clinicopathologic characteristics

TMPRSS2/ERG fusion was found to be the most common genetic event in prostate adenocarcinoma. There is a strong correlation between the fusion and ERG-positive immunostaining. Many studies showed racial variation in ERG expression in prostate cancer patients. There is no data however on the rate of ERG-positive cancer in Jordanian or Arab population. We evaluated the frequency and the significance of ERG fusion in Jordanian-Arab population using immunohistochemistry for ERG. The cohort included 193 prostate cancer specimens: 109 needle core biopsies, 45 radical prostatectomies, 37 transurethral resections of prostate, and 2 enucleation specimens. We found ERG reactivity in 64 (33.2%) of evaluated cases. The observed ERG frequency in the Jordanian-Arab population is lower than the one documented in North America, but it is higher than in Asian patient cohorts. The ERG positivity was significantly associated with lower baseline prostate-specific antigen but was unrelated to patient age, Gleason Score, or the novel Gleason Grade Groups. In the 45 prostatectomy cases, ERG did not correlate with the pathologic stage, margin, nodal status, and the biochemical recurrence, and it did not appear to represent an important prognosticator.

Expression of ERG Protein and TMRPSS2-ERG Fusion in Prostatic Carcinoma in Egyptian Patients

AIM

Prostate cancer (PCa) is the second most common cancers in men worldwide. Its incidence can be influenced by several risk factors including genetic susceptibility. Therefore the search for the expression of a certain gene (ERG) and its rearrangement could give us clues for proper identification of PCa. And the study of ERG expression and its comparison to FISH in Egyptian patients can show whether ERG immunophenotype could be used instead of FISH, as it is cheaper.

MATERIALS AND METHODS

This study was performed on 85 cases of PCa, showing 30 cases with HGPIN and 30 cases of prostatic hyperplasia. All were immunohistochemistry stained using ERG monoclonal rabbit antihuman antibody was used (clone: EP111). FISH analysis was performed in 38 biopsies of PCa cases to detect TMRPSS2-ERG rearrangement using the FISH ZytoLight TriCheck Probe (SPEC TMRPSS2-ERG).

RESULTS

ERG expression was found in 26% of PCa cases and 20% of HGPIN cases. FISH analysis showed fusion of 21 cases of PCa (out of 22 cases showing ERG immunoexpression).

CONCLUSION

Our findings emphasise that only malignant and pre-malignant cells and not benign cells from the prostate stain positive. ERG expression may offer a simpler, accurate and less costly alternative for evaluation of ERG fusion status in PCa.

Urinary Biomarker Panel to Improve Accuracy in Predicting Prostate Biopsy Result in Chinese Men with PSA 4-10 ng/mL

This study aims to evaluate the effectiveness and clinical performance of a panel of urinary biomarkers to diagnose prostate cancer (PCa) in Chinese men with PSA levels between 4 and 10 ng/mL. A total of 122 patients with PSA levels between 4 and 10 ng/mL who underwent consecutive prostate biopsy at three hospitals in China were recruited. First-catch urine samples were collected after an attentive prostate massage. Urinary mRNA levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The predictive accuracy of these biomarkers and prediction models was assessed by the area under the curve (AUC) of the receiver-operating characteristic (ROC) curve. The diagnostic accuracy of PCA3, PSGR, and MALAT-1 was superior to that of PSA. PCA3 performed best, with an AUC of 0.734 (95% CI: 0.641, 0.828) followed by MALAT-1 with an AUC of 0.727 (95% CI: 0.625, 0.829) and PSGR with an AUC of 0.666 (95% CI: 0.575, 0.749). The diagnostic panel with age, prostate volume, % fPSA, PCA3 score, PSGR score, and MALAT-1 score yielded an AUC of 0.857 (95% CI: 0.780, 0.933). At a threshold probability of 20%, 47.2% of unnecessary biopsies may be avoided whereas only 6.2% of PCa cases may be missed. This urinary panel may improve the current diagnostic modality in Chinese men with PSA levels between 4 and 10 ng/mL.

DNA alterations in the tumor genome and their associations with clinical outcome in prostate cancer

Although most prostate cancer (PCa) cases are not life-threatening, approximately 293 000 men worldwide die annually due to PCa. These lethal cases are thought to be caused by coordinated genomic alterations that accumulate over time. Recent genome-wide analyses of DNA from subjects with PCa have revealed most, if not all, genetic changes in both germline and PCa tumor genomes. In this article, I first review the major, somatically acquired genomic characteristics of various subtypes of PCa. I then recap key findings on the relationships between genomic alterations and clinical parameters, such as biochemical recurrence or clinical relapse, metastasis and cancer-specific mortality. Finally, I outline the need for, and challenges with, validation of recent findings in prospective studies for clinical utility. It is clearer now than ever before that the landscape of somatically acquired aberrations in PCa is highlighted by DNA copy number alterations (CNAs) and TMPRSS2-ERG fusion derived from complex rearrangements, numerous single nucleotide variations or mutations, tremendous heterogeneity, and continuously punctuated evolution. Genome-wide CNAs, PTEN loss, MYC gain in primary tumors, and TP53 loss/mutation and AR amplification/mutation in advanced metastatic PCa have consistently been associated with worse cancer prognosis. With this recently gained knowledge, it is now an opportune time to develop DNA-based tests that provide more accurate patient stratification for prediction of clinical outcome, which will ultimately lead to more personalized cancer care than is possible at present.

TMPRSS2-ERG gene fusion in Turkish patients with localized prostate cancer: results of radical prostatectomy specimens

OBJECTIVE

Our aim was to evaluate and determine the frequency of Transmembrane protease, serine 2 (TMPRSS2)-ERG fusion in Turkish patients with clinically localized prostate cancer by using immunohistochemistry and reveal its relationship with clinicopathologic variables.

MATERIAL AND METHODS

Radical prostatectomy specimens of 99 patients, who underwent radical retropubic prostatectomy for localized cancer, between January 2002 and December 2011 were analyzed in the study. To detect ERG fusions, monoclonal ERG antibodyclone ID: EPR3864 (Epitomics, San Diego, CA, USA) and monoclonal anti-ERG antibody (9FY) (BiocareMedical, LLC, USA) were used. The immunistochemical expression of ERG protein was assessed as positive or negative regardless of stain intensity. Patients' age, total and primary Gleason scores, PSA levels, prostate volumes, tumor volumes, tumor stages and perineural invasion status were analysed retrospectively. Total fusion rate and correlation between the variables and fusion were evaluated.

RESULTS

Mean age, prostate volume, tumor volume, PSA value of 99 patients were 62.02 years (±5.93), 50.02 cc (±20.67), 3.19 cc (±4.16), and 9.34 ng/mL (±3.37) respectively. TMPRSS2-ERG fusion was seen in 46 (46.5%) of 99 patients. When the variables analysed with independent samples t test to predict fusion (+) status, none of them was found to be statistically significant. When evaluated by logistic regression analysis for (+) or (-) status, only tumor stage was found to be statistically significantly correlated with fusion (p=0.049).

CONCLUSION

The incidence of TMPRSS-ERG fusion in patients with localised prostate cancer in our study with Turkish population was found as 46.5%. Only tumor stage correlated with TMPRSS2-ERG fusion.

Prognostic value of ERG, PTEN, CRISP3 and SPINK1 in predicting biochemical recurrence in prostate cancer

The established prognostic factors associated with prostatic adenocarcinoma are the Gleason score, pathological T staging and serum prostatic-specific antigen (PSA) level. However, these prognostic factors alone are not sufficient for predicting prognostic characteristics, including early stage or advanced prostate cancer, presence of metastasis or disease-related mortality. The purpose of the present study was to simultaneously evaluate the prognostic value and associations of four biomarkers, namely, transcriptional regulator ERG (ERG), phosphatase and tensin homolog (PTEN), cysteine-rich secretory protein 3 (CRISP3) and serine protease inhibitor Kazal type I (SPINK1), and to conduct risk stratification of prostate cancer for use in patient management. A total of 68 formalin-fixed, paraffin-embedded, prostate cancer samples from radical prostatectomies were obtained in the Kyung Hee University Hospital (Seoul, Korea) and were studied immunohistochemically for ERG, PTEN, CRISP3 and SPINK1 to determine the proportion and intensity of staining. SPINK1 expression was mutually exclusive of ERG expression (P=0.001). The loss of PTEN and high CRISP3 expression are unfavorable indicators for prostate cancer, as PTEN loss was associated with shorter biochemical recurrence (BCR) (P=0.039), and high CRISP3 expression was associated with increased BCR (P<0.001) and cancer-related mortalities (P=0.011). Using the combination of low PTEN and high CRISP3 expression enables attention to be focused on patients who exhibit a poor prognosis. Subgrouping of patients, into high-risk and low-risk categories, was correlated with BCR-free survival in prostate cancer upon multivariate analysis (P=0.030). Overall, low PTEN and high CRISP3 expression significantly characterize the subgroups of prostate cancer that have a poor prognosis for BCR.

The complexity of prostate cancer: genomic alterations and heterogeneity

Although prostate cancer is the most common malignancy to affect men in the Western world, the molecular mechanisms underlying its development and progression remain poorly understood. Like all cancers, prostate cancer is a genetic disease that is characterized by multiple genomic alterations, including point mutations, microsatellite variations, and chromosomal alterations such as translocations, insertions, duplications, and deletions. In prostate cancer, but not other carcinomas, these chromosome alterations result in a high frequency of gene fusion events. The development and application of novel high-resolution technologies has significantly accelerated the detection of genomic alterations, revealing the complex nature and heterogeneity of the disease. The clinical heterogeneity of prostate cancer can be partly explained by this underlying genetic heterogeneity, which has been observed between patients from different geographical and ethnic populations, different individuals within these populations, different tumour foci within the same patient, and different cells within the same tumour focus. The highly heterogeneous nature of prostate cancer provides a real challenge for clinical disease management and a detailed understanding of the genetic alterations in all cells, including small subpopulations, would be highly advantageous.

Comprehensive assessment for novel prostate cancer markers in the prostate-specific antigen era: focusing on Asians and Asian countries

We reviewed the current evidence for three novel prostate tumor markers (PCA3, TMPRSS2:ERG and proPSA) that have been recently reported predominantly in Western countries. We focus our attention on Asian men in both clinical and basic research studies. There have been no reports on the clinical usefulness of these three markers for Asians living in Western countries. In Asian countries, evidence for the clinical usefulness of PCA3 and proPSA-related indices including Prostate Health Index is being accumulated, mainly in Japan. The process for how a novel marker is approved in the clinical setting is also discussed.

Correlation of ERG immunohistochemistry with molecular detection of TMPRSS2-ERG gene fusion

Aims

TMPRSS2/E26 transformation-specific (ETS) family gene fusion in prostate carcinoma (PCa) can be detected by several methods including immunohistochemistry (IHC) for ETS-related gene (ERG), the diagnostic utility of which has not been clearly defined.

Methods

We explored TMPRSS2-ERG gene rearrangement status in 132 patients with PCa with four detection methods including fluorescence in situ hybridisation for TMPRSS2-ERG fusion, real-time reverse transcription PCR (RT-qPCR) for ERG and TMPRSS-ERG fusion transcript mRNA and IHC for ERG.

Results

Concordant results were found in 126 cases for the four detection methods and the remaining six cases showed discrepancy in one method: two cases in IHC, three cases in RT-qPCR for ERG and one case in RT-qPCR for fusion transcript. In discordant cases, the majority results were determined as final fusion status. Analysis of discrepancy cases for ERG IHC showed that weak immunoreactivity for ERG should be regarded as equivocal and that even strong immunoreactivity can be false positive. The overall incidence of TMPRSS-ERG gene fusion was 24%.

Conclusions

ERG IHC is a useful surrogate test for the detection of TMPRSS2-ERG gene fusion, but it needs to be interpreted with caution and definite judgement should not be based on IHC alone. A relatively low incidence of TMPRSS2-ERG gene fusion was demonstrated in this Korean cohort.

Expression of Peroxisome Proliferator Activated Receptor gamma in Prostatic Adenocarcinoma

Peroxisome proliferator-activated receptor gamma (PPAR-γ), a ligand-activated transcription factor has been investigated as the target for cancer treatment as well as metabolic disorders. Recent studies have demonstrated that PPAR-γ ligands are anti-tumorigenic in prostate cancer due to anti-proliferative and pro-differentiation effects. The aim of this study was to validate PPAR-γ expression in malignant and benign prostate tissues by immunohistochemistry and quantitative real-time polymerase chain reaction (PCR). A total of 730 prostatic adenocarcinomas (PCAs) including 63 whole sections from radical prostatectomy specimens and tissue microarrays containing 667 PCAs were subject to immunostaining for two PPAR-γ antibodies. Twenty-five benign prostate tissues and PCAs were selected for investigating mRNA expression by quantitative real-time PCR. 10.7% of PCAs (78/730) showed cytoplasmic immunoreactivity of PPAR-γ and no nuclear immunoreactivity was noted in PCAs. Most benign prostatic glands showed negative immunoreactivity of PPAR-γ except for variable weak cytoplasmic staining in some glands. Nuclear immunoreactivity of PPAR-γ was noted some central zone and verumontanum mucosal epithelium. The constitutive PPAR-γ mRNA showed significantly lower level in PCAs compared to that in the benign tissues. There was no difference of PPAR-γ mRNA expression between low (≤7) and high (>7) Gleason score groups. There was no association of PPAR-γ mRNA level or cytoplasmic immunostaining with Gleason grade or pathologic stage. Our study supported the evidence of extra-nuclear localization and nongenomic actions of PPAR-γ. Further studies are needed to assess the functional role of PPAR-γ and to validate its therapeutic implication in prostate cancer.

ERG oncoprotein expression in prostate carcinoma patients of different ethnicities

Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology of CaP initiation and progression between ethnic groups.

Transcription-mediated chimeric RNAs in prostate cancer: time to revisit old hypothesis?

Chromosomal rearrangements and fusion genes play important roles in tumor development and progression. Four high-frequency prostate cancer-specific fusion genes were recently reported in Chinese cases. We attempted to confirm one of the fusion genes, USP9Y-TTTY15, by reverse transcription PCR, but detected the presence of the USP9Y-TTTY15 fusion transcript in cancer samples, nonmalignant prostate tissues, and normal tissues from other organs, demonstrating that it is a transcription-induced chimeric RNA, which is commonly produced in normal tissues. In 105 prostate cancer samples and case-matched adjacent nonmalignant tissues, we determined the expression level of USP9Y-TTTY15 and a previously reported transcription-induced chimeric RNA, SLC45A3-ELK4. The expression levels of both chimeric RNAs vary greatly in cancer and normal cells. USP9Y-TTTY15 expression is neither higher in cancer than adjacent normal tissues, nor correlated with features of advanced prostate cancer. Although the expression level of SLC45A3-ELK4 is higher in cancer than normal cells, and a dramatic increase in its expression from normal to cancer cells is correlated with advanced disease, its expression level in cancer samples alone is not correlated with any clinical parameters. These data show that both chimeric RNAs contribute less to prostate carcinogenesis than previously reported.

Serine protease inhibitor Kazal type 1 promotes epithelial-mesenchymal transition through EGFR signaling pathway in prostate cancer

BACKGROUND

Overexpression of serine protease inhibitor Kazal type 1 (SPINK1) defines an aggressive molecular subtype of ETS fusion-negative prostate cancer (PCa) patients in western countries. However, how SPINK1 contributes to PCa invasion and metastasis is largely unknown.

METHODS

Fluorescence in situ hybridization and immunohistochemistry were utilized to detect ERG rearrangement, SPINK1 expression, and EGFR aberrations in a cohort of 211 PCa patients with radical prostatectomy. Real-time quantitative PCR and Western blotting were used to study the transcript and protein expression levels. Cellular distribution of E-cadherin and vimentin were observed by immunofluorescence. Cellular function was evaluated by siRNA, transwell, and wound healing assay, respectively.

RESULTS

SPINK1-induced Epithelial-mesenchymal transition (EMT) in benign prostate RWPE cells, manifested by acquisition of mesenchymal morphology, alternation of EMT markers as well as migration and invasion capabilities. Knockdown of SPINK1 in 22RV1 PCa cells results in up-regulation of E-cadherin and down-regulation of vimentin. SPINK1-induced EMT is mediated by EGFR, in which MAPK/MEK/ERK pathway is mainly involved. Connective tissue growth factor (CTGF) might be an important down-stream molecule of SPINK1-EGFR axis. Clinically, SPINK1 and EGFR were significantly co-overexpressed in a cohort of Chinese PCa patients (n > 200). SPINK1 is an unfavorable prognostic factor in Chinese PCas (P = 0.025).

CONCLUSIONS

These findings suggest that SPINK1 promotes EMT through EGFR signaling pathway in PCa and SPINK1 could be a new prognostic marker in Chinese PCas.

ERG rearrangement is associated with prostate cancer-related death in Chinese prostate cancer patients

Recently, ETS-related gene (ERG) gene rearrangements, phosphatase tensin homologue (PTEN) deletions and EGFR family aberrations were characterized as potential biomarkers for prostate cancer (PCa) patient management. Although ERG gene rearrangement has been identified in approximately 50% of localized prostate cancers in western countries, the prognostic significance of this critical molecular event remains unknown in Chinese patients. Using fluorescence in situ hybridization (FISH) and immunohistochemistry, we evaluated ERG, PTEN and EGFR family aberrations in a cohort of 224 Chinese prostate cancer patients diagnosed in transurethral resection of the prostate (TUR-P). Overall, ERG rearrangement was detected in 23.2% (44/190) cases, of which 54.5% (24/44) showed deletion of the 5'end of ERG. PTEN deletion was identified in 10.8% (19/176) cases. Amplification of EGFR and HER2 genes was present in 1.1% (2/178) and 5.8% (10/173) of cases, respectively. Significant correlation between ERG rearrangement and PTEN deletion was identified in this cohort. EGFR and HER2 aberrations occurred more frequently in PCas without ERG rearrangement than in those with ERG rearrangement, although this did not reach statistical significance. Overall, ERG rearrangement was associated with pre-operative PSA values (P = 0.038) and cancer-related death (P = 0.02), but not with the age, clinical T stage, Gleason score, or Ki-67 labeling index (LI). Notably, multivariate analysis including known prognostic markers revealed ERG rearrangement was an independent prognostic factor (P = 0.022). Additionally, ERG rearrangement status was helpful to identify patients with poor prognosis from PCa group with low Ki-67 LI. In summary, we reported that ERG rearrangement was associated with cancer-related death in Chinese PCa patients. Determination of ERG rearrangement status allows stratification of PCa patients into different survival categories.

Recurrent rearrangements in prostate cancer: causes and therapeutic potential

DNA damage and genetic rearrangements are hallmarks of cancer. However, gene fusions as driver mutations in cancer have classically been a distinction in leukemia and other rare instances until recently with the discovery of gene fusion events occurring in 50 to 75% of prostate cancer patients. The discovery of the TMPRSS2-ERG fusion sparked an onslaught of discovery and innovation resulting in a delineation of prostate cancer via a molecular signature of gene fusion events. The increased commonality of high-throughput sequencing data coupled with improved bioinformatics approaches not only elucidated the molecular underpinnings of prostate cancer progression, but the mechanisms of gene fusion biogenesis. Interestingly, the androgen receptor (AR), already known to play a significant role in prostate cancer tumorigenesis, has recently been implicated in the processes resulting in gene fusions by inducing the spatial proximity of genes involved in rearrangements, promoting the formation of double-strand DNA breaks (DSB), and facilitating the recruitment of proteins for non-homologous end-joining (NHEJ). Our increased understanding of the mechanisms inducing genomic instability may lead to improved diagnostic and therapeutic strategies. To date, the majority of prostate cancer patients can be molecularly stratified based on their gene fusion status thereby increasing the potential for tailoring more specific and effective therapies.

The molecular basis for ethnic variation and histological subtype differences in prostate cancer

Prostate cancer is a common malignancy among men in Western countries. Recently the morbidity and mortality of prostate cancer increase dramatically in several oriental countries including China. Rapidly evolving technology in molecular biology such as high-throughput sequencing and integrative analysis of genomic and transcriptomic landscapes have enabled the identification of key oncogenic events for prostate cancer initiation, progression and resistance to hormonal therapy. These surging data of prostate cancer genome also provide insights on ethnic variation and the differences in histological subtype of this disease. In this review, differences in the incidence of prostate cancer and the prevalence of main genetic alterations between Asian and Western populations are discussed. We also review the recent findings on the mechanisms underlying neuroendocrine differentiation of prostate cancer and the development of small cell neuroendocrine carcinoma after androgen deprivation therapy.

[Personalized urooncology based on molecular uropathology: what is the future?]

Targeted therapies and biomarker validation are key drivers in the advancement of personalized oncology which is a growing topic in all clinical areas. Compared with other professions, such as pulmonology and gynecology, development in urology has so far been retarded but has recently gained increasing momentum. A basis for this is the currently growing and in future accelerated application of new knowledge derived from molecular biology in the field of uropathology. The rapid gain of knowledge is driven by a whole new class of analytical methods, such as massively parallel sequencing (deep sequencing or next generation sequencing), which enables analysis of virtually a new universe of potential biomarkers. This article describes the emerging paradigm shift in molecular pathological diagnostics of urological tumors using the example of prostate cancer.

Preliminary Results of Noninvasive Detection of TMPRSS2:ERG Gene Fusion in a Cohort of Patients With Localized Prostate Cancer

Purpose

The aim of this study was to evaluate TMPRSS2:ERG fusion rates in tissue, urine, blood, and pubic hair samples in a cohort of patients with localized prostate cancer and to correlate these findings with various clinicopathological parameters.

Materials and Methods

A cohort of 40 patients undergoing radical prostatectomy for localized prostate cancer (RRP group) and 10 control patients undergoing prostate biopsy were enrolled between 2006 and 2008. Urine, pubic hair, and peripheral blood samples were obtained following prostatic massage before the needle biopsy or radical prostatectomy. Quantitative polymerase chain reaction analysis was performed on all collected samples.

Results

The patients' mean age was 62.4 (±5.5) years. We observed higher expressions of TMPRSS2:ERG fusion in tissue, urine, and blood samples from the RRP group than in samples from the control group. Overall, the fusion was present in urine samples of 23 RRP patients (57.5%). To predict high-stage cancer (>T3a), the Gleason score was the only significant factor in the logistic regression analysis (score, 10.579; p=0.001). Quantitative evaluation of the gene fusion in tissue (Pearson r=0.36, p=0.011) and urine (Pearson r=0.34, p=0.014) samples had a significant positive correlation with the preoperative prostate-specific antigen level.

Conclusions

Urine sediments collected after prostatic massage appear to be a feasible noninvasive method of detecting TMPRSS2:ERG fusion. The Gleason score is the only significant factor to predict high-stage cancer (>T3a). No correlation between TMPRSS2:ERG gene fusion status and tumor stage, Gleason grade, prostate-specific antigen level, or surgical margin status was observed.

Prostate cancer research in China

Prostate cancer (PCa) research in China has been on a rocketing trend in recent years. The first genome-wide association study (GWAS) in China identified two new PCa risk associated single nucleotide polymorphisms (SNPs). Next generation sequencing is beginning to be used, yielding novel findings: gene fusions, long non-coding RNAs and other variations. Mechanisms of PCa progression have been illustrated while various diagnosis biomarkers have been investigated extensively. Personalized therapy based on genetic factors, nano-medicine and traditional Chinese medicine has been the focus of experimental therapeutic research for PCa. This review intends to shed light upon the recent progress in PCa research in China and points out the possible breakthroughs in the future.

A novel four-color fluorescence in situ hybridization assay for the detection of TMPRSS2 and ERG rearrangements in prostate cancer

Since the identification of the TMPRSS2-ERG rearrangement as the most common fusion event in prostate cancer, various methods have been developed to detect this rearrangement and to study its prognostic significance. We report a novel four-color fluorescence in situ hybridization (FISH) assay that detects not only the typical TMPRSS2-ERG fusion but also alternative rearrangements of the TMPRSS2 or ERG gene. We validated this assay on fresh, frozen, or formalin-fixed paraffin-embedded prostate cancer specimens, including cell lines, primary prostate cancer tissues, xenograft tissues derived from metastatic prostate cancer, and metastatic tissues from castration-resistant prostate cancer (CRPC) patients. When compared with either reverse transcription-polymerase chain reaction or the Gen-Probe method as the technical reference, analysis using the four-color FISH assay demonstrated an analytical sensitivity of 94.5% (95% confidence interval [CI] 0.80-0.99) and specificity of 100% (95% CI 0.89-1.00) for detecting the TMPRSS2-ERG fusion. The TMPRSS2-ERG fusion was detected in 41% and 43% of primary prostate cancer (n = 59) and CRPC tumors (n = 82), respectively. Rearrangements other than the typical TMPRSS2-ERG fusion were confirmed by karyotype analysis and found in 7% of primary cancer and 13% of CRPC tumors. Successful karyotype analyses are reported for the first time on four of the xenograft samples, complementing the FISH results. Analysis using the four-color FISH assay provides sensitive detection of TMPRSS2 and ERG gene rearrangements in prostate cancer.

ERG immunohistochemistry and clinicopathologic characteristics in Korean prostate adenocarcinoma patients

Background

Transmembrane protease serine 2-ETS related gene (TMPRSS2-ERG) gene fusion, the most common genetic alternation in prostate cancer, is associated with protein expression of the oncogene ERG. Recently, an immunohistochemical staining method using an anti-ERG antibody was shown to have a strong correlation with altered ERG protein expression.

Methods

We analyzed a total of 303 radical prostatectomy specimens (obtained from Korean prostate cancer cases) using a constructed tissue microarray and ERG immunohistochemical staining. Thereafter, we evaluated the association between ERG expression and clinicopathological factors.

Results

The ERG-positive rate was 24.4% (74/303) and significantly higher ERG expression was observed in the subgroup with a lower Gleason score (p=0.004). Analysis of the histologic pattern of prostate adenocarcinomas revealed that tumors with discrete glandular units (Gleason pattern 3) displayed higher frequency of ERG expression (p=0.016). The ERG-positive rate was lower than that found (approximately 50%) in studies involving western populations. Other factors including age, tumor volume, initial protein-specific antigen level, a pathological stage and margin status were not significantly related with the ERG expression.

Conclusions

ERG immunohistochemical staining is significantly higher in tumors with well-formed glands and is associated with a lower Gleason score.

The TMPRSS2:ERG rearrangement, ERG expression, and prostate cancer outcomes: a cohort study and meta-analysis

BACKGROUND

Whether the genomic rearrangement transmembrane protease, serine 2 (TMPRSS2):v-ets erythroblastosis virus E26 oncogene homolog (ERG) has prognostic value in prostate cancer is unclear.

METHODS

Among men with prostate cancer in the prospective Physicians' Health and Health Professionals Follow-Up Studies, we identified rearrangement status by immunohistochemical assessment of ERG protein expression. We used Cox models to examine associations of ERG overexpression with biochemical recurrence and lethal disease (distant metastases or cancer-specific mortality). In a meta-analysis including 47 additional studies, we used random-effects models to estimate associations between rearrangement status and outcomes.

RESULTS

The cohort consisted of 1,180 men treated with radical prostatectomy between 1983 and 2005. During a median follow-up of 12.6 years, 266 men experienced recurrence and 85 men developed lethal disease. We found no significant association between ERG overexpression and biochemical recurrence [hazard ratio (HR), 0.99; 95% confidence interval (CI), 0.78-1.26] or lethal disease (HR, 0.93; 95% CI, 0.61-1.43). The meta-analysis of prostatectomy series included 5,074 men followed for biochemical recurrence (1,623 events), and 2,049 men followed for lethal disease (131 events). TMPRSS2:ERG was associated with stage at diagnosis [risk ratio (RR)(≥T3 vs. T2), 1.23; 95% CI, 1.16-1.30) but not with biochemical recurrence (RR, 1.00; 95% CI, 0.86-1.17) or lethal disease (RR, 0.99; 95% CI, 0.47-2.09).

CONCLUSIONS

These results suggest that TMPRSS2:ERG, or ERG overexpression, is associated with tumor stage but does not strongly predict recurrence or mortality among men treated with radical prostatectomy.

IMPACT

This is the largest prospective cohort study to examine associations of ERG overexpression and lethal prostate cancer among men treated with radical prostatectomy.

Prostate cancer as a model system for genetic diversity in tumors

This chapter will summarize novel understandings of the early molecular events in prostatic carcinogenesis that may underlie both the genetic and clinical heterogeneity. Areas covered include preneoplasia, stem cell concepts, telomere abnormalities, and the nature of tumor-stromal interactions. The oncogenomics of prostate cancer is reviewed with emphasis on androgen signaling, ETS gene family aberrations, and PTEN deletion. The notion that "field cancerization," coupled with genomic instability may explain both the occurrence of multifocal disease, and the recent observations of genetic diversity of ERG alteration in individual tumors are discussed. Collectively, genomic studies are rapidly moving human prostate cancer closer to the promise of personalized medicine, so that specific genetic profiles of individual tumors will determine the best therapeutic approaches.