TMPRSS2-ERG gene fusion is associated with low Gleason scores and not with high-grade morphological features

Molecular complexity of intraductal carcinoma of the prostate

Intraductal carcinoma of the prostate (IDC-P) is an aggressive subtype of prostate cancer characterized by the growth of tumor cells within the prostate ducts. It is often found alongside invasive carcinoma and is associated with poor prognosis. Understanding the molecular mechanisms driving IDC-P is crucial for improved diagnosis, prognosis, and treatment strategies. This review summarizes the molecular characteristics of IDC-P and their prognostic indications, comparing them to conventional prostate acinar adenocarcinoma, to gain insights into its unique behavior and identify potential therapeutic targets.

Unravelling the Role of P300 and TMPRSS2 in Prostate Cancer: A Literature Review

Prostate cancer is one of the most common malignant diseases in men, and it contributes significantly to the increased mortality rate in men worldwide. This study aimed to review the roles of p300 and TMPRSS2 (transmembrane protease, serine 2) in the AR (androgen receptor) pathway as they are closely related to the development and progression of prostate cancer. This paper represents a library-based study conducted by selecting the most suitable, up-to-date scientific published articles from online journals. We focused on articles that use similar techniques, particularly those that use prostate cancer cell lines and immunohistochemical staining to study the molecular impact of p300 and TMPRSS2 in prostate cancer specimens. The TMPRSS2:ERG fusion is considered relevant to prostate cancer, but its association with the development and progression as well as its clinical significance have not been fully elucidated. On the other hand, high p300 levels in prostate cancer biopsies predict larger tumor volumes, extraprostatic extension of disease, and seminal vesicle involvement at prostatectomy, and may be associated with prostate cancer progression after surgery. The inhibition of p300 has been shown to reduce the proliferation of prostate cancer cells with TMPRSS2:ETS (E26 transformation-specific) fusions, and combining p300 inhibitors with other targeted therapies may increase their efficacy. Overall, the interplay between the p300 and TMPRSS2 pathways is an active area of research.

Relationship between Proclarix and the Aggressiveness of Prostate Cancer

INTRODUCTION

Proclarix is a CE-marked test that provides the risk of clinically significant prostate cancer (csPCa), ranging from 0% to 100%, based on the serum measurement of Thrombospondin-1, cathepsin D, prostate-specific antigen (PSA), and percentage of free PSA in addition to age. We hypothesize that Proclarix could be correlated with PCa aggressiveness. We analyzed the association of this new biomarker with four surrogates of aggressiveness: grade group (GG) in the biopsy, clinical stage, risk of biochemical recurrence after primary treatment of localized PCa, and pathology in the surgical specimen.

MATERIAL AND METHODS

This is a retrospective study from 606 men with suspicion of PCa [PSA of ≥ 3.0 ng/mL and/or abnormal digital rectal examination (DRE)], in whom Proclarix was assessed (0-100%). The GG was defined by the International Society of Urological Pathology categories. The TNM was used for clinical staging (cT based on DRE, whereas cN and cM were established with computed tomography and 99-technetium bone scintigraphy). The risk of biochemical recurrence of localized PCa after primary treatment was defined by combining PSA, GG, and cT. Finally, an unfavorable pathology in a surgical specimen was defined as GG > 2 or pT ≥ 3.

RESULTS

The median age of the cohort was 67 years old, with a median PSA of 7 ng/mL and a rate of abnormal DRE of 23.3%. CsPCa was detected in 254 men (41.9%), with a median Proclarix of 60.1% compared with 37.3% obtained in patients with insignificant PCa and 20.7% in men without PCa. Among patients with GG > 3, Proclarix was significantly higher (58.2%) than in those with GG of 3 or lower (33.1%, p < 0.001). Men with localized tumors exhibited a Proclarix median of 37.3% compared with those with advanced disease (60.1%, p < 0.001). Proclarix levels among 197 patients with low and intermediate risk of biochemical recurrence were 24.9% and 35.0%, respectively, significantly lower compared with patients with high-risk disease (58.7%, p < 0.001). Unfavorable pathology was observed in 35 patients out of the 79 who underwent radical prostatectomy, with a Proclarix median of 35.7% compared with 23.7% obtained in patients with favorable pathology (p = 0.013). Proclarix and magnetic resonance imaging were independent predictors of the four surrogates of aggressiveness analyzed.

CONCLUSION

There is a correlation between Proclarix and the aggressiveness of PCa.

Metabolic pathways enriched according to ERG status are associated with biochemical recurrence in Hispanic/Latino patients with prostate cancer

BACKGROUND

The role of ERG-status molecular subtyping in prognosis of prostate cancer (PCa) is still under debate. In this study, we identified differentially expressed genes (DEGs) according to ERG-status to explore their enriched pathways and implications in prognosis in Hispanic/Latino PCa patients.

METHODS

RNA from 78 Hispanic PCa tissues from radical prostatectomies (RP) were used for RNA-sequencing. ERG_high /ERG_low tumor groups were determined based on the 1.5-fold change median expression in non-tumor samples. DEGs with a False Discovery Rate (FDR) < 0.01 and a fold change >2 were identified between ERG_high and ERG_low tumors and submitted to enrichment analysis in MetaCore. Survival and association analyses were performed to evaluate biochemical recurrence (BCR)-free survival.

RESULTS

The identification of 150 DEGs between ERG_high and ERG_low tumors revealed clustering of most of the non-BCR cases (60%) into de ERG_high group and most of the BCR cases (60.8%) in ERG_low group. Kaplan-Meier survival curves showed a worst BCR-free survival for ERG_low patients, and a significant reduced risk of BCR was observed for ERG_high cases (OR = 0.29 (95%CI, 0.10-0.8)). Enrichment pathway analysis identified metabolic-related pathways, such as the renin-angiotensin system and angiotensin maturation system, the linoleic acid metabolism, and polyamines metabolism in these ERG groups.

CONCLUSIONS

ERG_low tumor cases were associated with poor BCR-free survival in our Hispanic/Latino patients, with metabolism-related pathways altered in the BCR progression.

IMPACT

Our findings suggest the need to dissect the role of diet, metabolism, and lifestyle as risk factors for more aggressive PCa subtypes.

Leveraging artificial intelligence to predict ERG gene fusion status in prostate cancer

Background

TMPRSS2-ERG gene rearrangement, the most common E26 transformation specific (ETS) gene fusion within prostate cancer, is known to contribute to the pathogenesis of this disease and carries diagnostic annotations for prostate cancer patients clinically. The ERG rearrangement status in prostatic adenocarcinoma currently cannot be reliably identified from histologic features on H&E-stained slides alone and hence requires ancillary studies such as immunohistochemistry (IHC), fluorescent in situ hybridization (FISH) or next generation sequencing (NGS) for identification.

Methods

Objective

We accordingly sought to develop a deep learning-based algorithm to identify ERG rearrangement status in prostatic adenocarcinoma based on digitized slides of H&E morphology alone.

Design

Setting, and Participants: Whole slide images from 392 in-house and TCGA cases were employed and annotated using QuPath. Image patches of 224 × 224 pixel were exported at 10 ×, 20 ×, and 40 × for input into a deep learning model based on MobileNetV2 convolutional neural network architecture pre-trained on ImageNet. A separate model was trained for each magnification. Training and test datasets consisted of 261 cases and 131 cases, respectively. The output of the model included a prediction of ERG-positive (ERG rearranged) or ERG-negative (ERG not rearranged) status for each input patch.

Outcome measurements and statistical analysis: Various accuracy measurements including area under the curve (AUC) of the receiver operating characteristic (ROC) curves were used to evaluate the deep learning model.

Results and Limitations

All models showed similar ROC curves with AUC results ranging between 0.82 and 0.85. The sensitivity and specificity of these models were 75.0% and 83.1% (20 × model), respectively.

Conclusions

A deep learning-based model can successfully predict ERG rearrangement status in the majority of prostatic adenocarcinomas utilizing only H&E-stained digital slides. Such an artificial intelligence-based model can eliminate the need for using extra tumor tissue to perform ancillary studies in order to assess for ERG gene rearrangement in prostatic adenocarcinoma.

Racial disparity in prostate cancer in the African American population with actionable ideas and novel immunotherapies

BACKGROUND

African Americans (AAs) in the United States are known to have a higher incidence and mortality for Prostate Cancer (PCa). The drivers of this epidemiological disparity are multifactorial, including socioeconomic factors leading to lifestyle and dietary issues, healthcare access problems, and potentially tumor biology.

RECENT FINDINGS

Although recent evidence suggests once access is equal, AA men have equal outcomes to Caucasian American (CA) men, differences in PCa incidence remain, and there is much to do to reverse disparities in mortality across the USA. A deeper understanding of these issues, both at the clinical and molecular level, can facilitate improved outcomes in the AA population. This review first discusses PCa oncogenesis in the context of its diverse hallmarks before benchmarking key molecular and genomic differences for PCa in AA men that have emerged in the recent literature. Studies have emphasized the importance of tumor microenvironment that contributes to both the unequal cancer burden and differences in clinical outcome between the races. Management of comorbidities like obesity, hypertension, and diabetes will provide an essential means of reducing prostate cancer incidence in AA men. Although requiring further AA specific research, several new treatment strategies such as immune checkpoint inhibitors used in combination PARP inhibitors and other emerging vaccines, including Sipuleucel-T, have demonstrated some proven efficacy.

CONCLUSION

Genomic profiling to integrate clinical and genomic data for diagnosis, prognosis, and treatment will allow physicians to plan a "Precision Medicine" approach to AA men. There is a pressing need for further research for risk stratification, which may allow early identification of AA men with higher risk disease based on their unique clinical, genomic, and immunological profiles, which can then be mapped to appropriate clinical trials. Treatment options are outlined, with a concise description of recent work in AA specific populations, detailing several targeted therapies, including immunotherapy. Also, a summary of current clinical trials involving AA men is presented, and it is important that policies are adopted to ensure that AA men are actively recruited. Although it is encouraging that many of these explore the lifestyle and educational initiatives and therapeutic interventions, there is much still work to be done to reduce incidence and mortality in AA men and equalize current racial disparities.

Tissue- and Liquid-Based Biomarkers in Prostate Cancer Precision Medicine

Worldwide, prostate cancer (PC) is the second-most-frequently diagnosed male cancer and the fifth-most-common cause of all cancer-related deaths. Suspicion of PC in a patient is largely based upon clinical signs and the use of prostate-specific antigen (PSA) levels. Although PSA levels have been criticised for a lack of specificity, leading to PC over-diagnosis, it is still the most commonly used biomarker in PC management. Unfortunately, PC is extremely heterogeneous, and it can be difficult to stratify patients whose tumours are unlikely to progress from those that are aggressive and require treatment intensification. Although PC-specific biomarker research has previously focused on disease diagnosis, there is an unmet clinical need for novel prognostic, predictive and treatment response biomarkers that can be used to provide a precision medicine approach to PC management. In particular, the identification of biomarkers at the time of screening/diagnosis that can provide an indication of disease aggressiveness is perhaps the greatest current unmet clinical need in PC management. Largely through advances in genomic and proteomic techniques, exciting pre-clinical and clinical research is continuing to identify potential tissue, blood and urine-based PC-specific biomarkers that may in the future supplement or replace current standard practices. In this review, we describe how PC-specific biomarker research is progressing, including the evolution of PSA-based tests and those novel assays that have gained clinical approval. We also describe alternative diagnostic biomarkers to PSA, in addition to biomarkers that can predict PC aggressiveness and biomarkers that can predict response to certain therapies. We believe that novel biomarker research has the potential to make significant improvements to the clinical management of this disease in the near future.

Mapping Isoform Abundance and Interactome of the Endogenous TMPRSS2-ERG Fusion Protein by Orthogonal Immunoprecipitation-Mass Spectrometry Assays

TMPRSS2-ERG gene fusion, a molecular alteration found in nearly half of primary prostate cancer cases, has been intensively characterized at the transcript level. However limited studies have explored the molecular identity and function of the endogenous fusion at the protein level. Here, we developed immunoprecipitation-mass spectrometry assays for the measurement of a low-abundance T1E4 TMPRSS2-ERG fusion protein, its isoforms, and its interactome in VCaP prostate cancer cells. Our assays quantified total ERG (∼27,000 copies/cell) and its four unique isoforms and revealed that the T1E4-ERG isoform accounted for 52 ± 3% of the total ERG protein in VCaP cells, and 50 ± 11% in formalin-fixed paraffin-embedded prostate cancer tissues. For the first time, the N-terminal peptide (methionine-truncated and N-acetylated TASSSSDYGQTSK) unique for the T1/E4 fusion was identified. ERG interactome profiling with the C-terminal, but not the N-terminal, antibodies identified 29 proteins, including mutually exclusive BRG1- and BRM-associated canonical SWI/SNF chromatin remodeling complexes. Our sensitive and selective IP-SRM assays present alternative tools to quantify ERG and its isoforms in clinical samples, thus paving the way for development of more accurate diagnostics of prostate cancer.

Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers. I. Molecular Biomarkers in Prostate Cancer

The combined clinical and molecular heterogeneity of prostate cancer necessitates the use of prognostic, predictive, and diagnostic biomarkers to assist the clinician with treatment selection. The pathologist plays a critical role in guiding molecular biomarker testing in prostate cancer and requires a thorough knowledge of the current testing options. In the setting of clinically localized prostate cancer, prognostic biomarkers such as Ki-67 labeling, PTEN loss or mRNA-based genomic signatures can be useful to help determine whether definitive therapy is required. In the setting of advanced disease, predictive biomarkers, such as the presence of DNA repair deficiency mediated by BRCA2 loss or mismatch repair gene defects, may suggest the utility of poly-ADP ribosylase inhibition or immune checkpoint blockade. Finally, androgen receptor-related biomarkers or diagnostic biomarkers indicating the presence of small cell neuroendocrine prostate cancer may help guide the use of androgen receptor signaling inhibitors and chemotherapy. In this review, we examine the current evidence for several prognostic, predictive and diagnostic tissue-based molecular biomarkers in prostate cancer management. For each assay, we summarize a recent survey of the International Society of Urology Pathology (ISUP) members on current testing practices and include recommendations for testing that emerged from the ISUP Working Group on Molecular Pathology of Prostate Cancer and the 2019 Consultation Conference on Molecular Pathology of Urogenital Cancers.

The Role of AMACR, CD10, TMPRSS2-ERG, and p27 Protein Expression Among Different Gleason Grades of Prostatic Adenocarcinoma on Needle Biopsy

OBJECTIVE

We examined the immunohistochemical expression of α-methyl acyl coenzyme A racemase (AMACR), CD10, TMPRSS2-ERG, and p27 in prostate adenocarcinoma tumors with different Gleason growth patterns and nonneoplastic prostate tissues to elucidate their roles in prostate carcinogenesis and histological aggressiveness.

MATERIAL AND METHODS

In total, 80 archival core biopsy tissues diagnosed as prostate carcinoma, benign prostate hyperplasia, and atrophy cases were included. Immunoreactivity was evaluated by calculating the percentage of positively stained cells and the staining intensity. The mean values and test of significance were obtained using the Kruskal-Wallis test.

RESULTS

We obtained mostly intense immunoreactivity for AMACR, CD10, and ERG in adenocarcinomas. Although no significant differences were noted regarding AMACR and ERG expression, samples with Gleason growth patterns 3 and 5 tended to be strongly positive for ERG. Pattern 3 tumors exhibited the weakest positivity for CD10. The p27 expression was strong and diffuse in nonneoplastic prostate tissues. The loss of p27 expression was more frequent for pattern 5 tumors.

CONCLUSION

ERG and AMACR were powerful markers to detect cancer. Especially, ERG is evident in early tumors may reflect its interaction with functional androgen receptors in cancer initiation. Pattern 5 tumors associated with stroma may have been exposed to more stromal substrates and upregulate their CD10 content as a protein degrader. We suggest that CD10 expression is associated with an increasing tumor grade. Decreased concentrations of p27 protein might be implicated in prostate carcinogenesis and may be a useful immunohistochemical adjunct in predicting histological aggressiveness.

Historical and contemporary perspectives on cribriform morphology in prostate cancer

The Gleason scoring system is widely used for the grading and prognostication of prostate cancer. A Gleason pattern 4 subtype known as cribriform morphology has now been recognized as an aggressive and often lethal pattern of prostate cancer. The vast majority of published and ongoing prostate cancer studies still do not acknowledge the prognostic differences between various Gleason pattern 4 morphologies. As a result, current treatment recommendations are likely to be imprecise and not tailored towards patients who are most likely to die from the disease. Use of active surveillance for patients with Gleason score 3 + 4 prostate cancer has been suggested. However, the success of such paradigms would require cribriform morphology to be reported at the time of prostate biopsy, as patients harbouring such a pattern are poor candidates for surveillance. To date, only a limited number of studies have described the molecular alterations that occur in the cribriform morphological pattern. Further refinement of prostate cancer grading paradigms to distinguish cribriform from noncribriform Gleason pattern 4 is essential.

African American Specific Gene Panel Predictive of Poor Prostate Cancer Outcome

PURPOSE

Most prostate cancer in African American men lacks the ETS (E26 transforming specific) family fusion event (ETS-). We aimed to establish clinically relevant biomarkers in African American men by studying ETS dependent gene expression patterns to identified race specific genes predictive of outcomes.

MATERIALS AND METHODS

Two multicenter cohorts of a total of 1,427 men were used for the discovery and validation (635 and 792 men, respectively) of race specific predictive biomarkers. We used false discovery rate adjusted q values to identify race and ETS dependent genes which were differentially expressed in African American men who experienced biochemical recurrence within 5 years. Principal component modeling along with survival analysis was done to assess the accuracy of the gene panel in predicting recurrence.

RESULTS

We identified 3,047 genes which were differentially expressed based on ETS status. Of these genes 362 were differentially expressed in a race specific manner (false discovery rate 0.025 or less). A total of 81 genes were race specific and over expressed in African American men who experienced biochemical recurrence. The final gene panel included APOD, BCL6, EMP1, MYADM, SRGN and TIMP3. These genes were associated with 5-year biochemical recurrence (HR 1.97, 95% CI 1.27-3.06, p = 0.002) and they improved the predictive accuracy of clinicopathological variables only in African American men (60-month time dependent AUC 0.72).

CONCLUSIONS

In an effort to elucidate biological features associated with prostate cancer aggressiveness in African American men we identified ETS dependent biomarkers predicting early onset biochemical recurrence only in African American men. Thus, these ETS dependent biomarkers representing ideal candidates for biomarkers of aggressive disease in this patient population.

[Prostate pathology recommendations from the Uropathology working group of the Spanish Society of Pathology]

These guidelines from the uropathology working group of the Spanish Society of Pathology (SEAP) are based on the European and ISUP 2015 recommendations and those of the College of American Pathologists, as well as the latest WHO 2016, TNM (AJCC) 2017 classifications. They include recommendations for specimen sampling, macro- and microscopic examination and immunohistochemistry. Gleason patterns are specified: Gleason pattern 3 includes hyperplastic, atrophic and microcystic glands, while pattern 4 includes all cribriform or glomeruloid glands. The Gleason score in prostatectomy specimens may change; if a tertiary pattern occurs in more than 5% of the tumour, it becomes a secondary pattern. In both biopsies and prostatectomy specimens, if the Gleason score is 7, the percentage of pattern 4 should be stated. Gleason scoring in tumor variants and special situations should also be specified. These recommendations should be adapted according to the resources available.

DNA damage repair alterations are frequent in prostatic adenocarcinomas with focal pleomorphic giant-cell features

AIMS

Prostatic adenocarcinomas with focal pleomorphic giant-cell features constitute a rare tumour subtype with abysmal clinical outcomes. More than one-third of patients with this histology die within a year of the initial diagnosis of prostate cancer. We aimed to perform molecular profiling of these tumors to identify potential therapeutic targets.

METHODS AND RESULTS

Here, we performed next-generation sequencing with a highly validated targeted panel (UW-OncoPlex) on somatic tumour DNA extracted from eight cases of prostatic adenocarcinoma with focal pleomorphic giant-cell features, including cases with and without prior treatment for prostate cancer. We found that DNA damage repair mutations are common in this rare subset of prostate tumours, with two of eight having bi-allelic pathogenic mutations in homologous DNA repair genes (including BRCA2 and NBN) and two of eight having bi-allelic pathogenic mutations in mismatch repair genes (including MSH2 and MLH1).

CONCLUSION

These data are consistent with emerging data showing that DNA repair alterations are enriched among castration-resistant prostate cancer and aggressive subsets of primary tumours. Given that these patients are potential candidates for poly(ADP-ribose) polymerase inhibitor and/or immune checkpoint blockade, and have a poor prognosis with standard therapy, we recommend that tumour and germline DNA sequencing with or without mismatch repair protein immunohistochemistry be considered for all prostatic adenocarcinomas with focal pleomorphic giant-cell features.

The Secret Life of Translation Initiation in Prostate Cancer

Prostate cancer (PCa) is the second most prevalent cancer in men worldwide. Despite the advances understanding the molecular processes driving the onset and progression of this disease, as well as the continued implementation of screening programs, PCa still remains a significant cause of morbidity and mortality, in particular in low-income countries. It is only recently that defects of the translation process, i.e., the synthesis of proteins by the ribosome using a messenger (m)RNA as a template, have begun to gain attention as an important cause of cancer development in different human tissues, including prostate. In particular, the initiation step of translation has been established to play a key role in tumorigenesis. In this review, we discuss the state-of-the-art of three key aspects of protein synthesis in PCa, namely, misexpression of translation initiation factors, dysregulation of the major signaling cascades regulating translation, and the therapeutic strategies based on pharmacological compounds targeting translation as a novel alternative to those based on hormones controlling the androgen receptor pathway.

Comparison of ERG and SPINK1 expression among incidental and metastatic prostate cancer in Japanese men

BACKGROUND

TMPRSS2:ERG fusion is the most common genetic event in prostate cancer (PCa). However, its association with prognosis is controversial. Overexpression of serine protease inhibitor Kazal-type 1 (SPINK1) was almost exclusively defined in ERG-negative PCa in most studies. This study aimed to determine the association between ERG and SPINK1 expression and the biological aggressiveness of PCa by analyzing their expression in incidental and metastatic cohorts.

METHODS

A total of 143 cystoprostatectomy specimens of invasive bladder cancer and 98 biopsy specimens from de novo metastatic PCa were analyzed. The prostate gland of cystoprostatectomy specimens was fixed and sliced in step sections. Immunohistochemistry of ERG and SPINK1 was conducted, and the results were correlated with the clinicopathological characteristics of the patients.

RESULTS

The overall prevalence of incidental cancer was 32.2% (46/143). The frequencies of both ERG and SPINK1 expression were not significantly different between incidental and metastatic cohorts (15.2% and 14.3%; P = 1.00, and 6.5% and 12.2%; P = 0.38, respectively). In the metastatic cohort, any pre-treatment factors were not significantly associated with the frequencies of ERG and SPINK1 expression. However, SPINK1 expression was significantly associated with a shorter time to castration-resistant PCa (CRPC) (P = 0.048). Meanwhile, overall survival was not significantly associated with the expression status of ERG and SPINK1 (P = 0.71).

CONCLUSIONS

ERG and SPINK1 expression may not have significant influence on the metastatic behavior of PCa. SPINK1 expression was significantly associated with a shorter time to CRPC in metastatic PCa. The expression profile of ERG and SPINK1 may be a useful predictor for effect of androgen deprivation therapy in patients with metastatic castration-sensitive PCa.

Large-Gland Proliferations of the Prostate

Large-gland proliferations of the prostate have gained considerable attention in the past decade. The differential diagnosis is quite broad but can be refined using histologic criteria and, sometimes, immunostains. Pathologists have come to realize that cribriform and intraductal as well as ductal carcinomas are particularly aggressive patterns, and should name them in diagnostic reporting when present.

Prostate Cancer Disparities by Race and Ethnicity: From Nucleotide to Neighborhood

Prostate cancer (CaP) incidence, morbidity, and mortality rates vary substantially by race and ethnicity, with African American men experiencing among the highest CaP rates in the world. The causes of these disparities are multifactorial and complex, and likely involve differences in access to screening and treatment, exposure to CaP risk factors, variation in genomic susceptibility, and other biological factors. To date, the proportion of CaP that can be explained by environmental exposures is small and differences in the role factors play by race or ethnicity is poorly understood. In the absence of additional data, it is likely that environmental factors do not contribute greatly to CaP disparities. In contrast, CaP has one of the highest heritabilities of all major cancers and many CaP susceptibility genes have been identified. Some CaP loci, including the risk loci found at chromosome 8q24, have consistent effects in all racial/ethnic groups studied to date. However, replication of many susceptibility loci across race or ethnicity remains limited. It is likely that inequities in health care access strongly influences CaP disparities. CaP is a disease with a complex multifactorial etiology, and therefore any approach attempting to address racial/ethnic disparities in CaP must consider the many sources that influence risk, outcomes, and disparities.

Genome-Based Classification and Therapy of Prostate Cancer

In the past decade, multi-national and multi-center efforts were launched to sequence prostate cancer genomes, transcriptomes, and epigenomes with the aim of discovering the molecular underpinnings of tumorigenesis, cancer progression, and therapy resistance. Multiple biological markers and pathways have been discovered to be tumor drivers, and a molecular classification of prostate cancer is emerging. Here, we highlight crucial findings of these genome-sequencing projects in localized and advanced disease. We recapitulate the utility and limitations of current clinical practices to diagnosis, prognosis, and therapy, and we provide examples of insights generated by the molecular profiling of tumors. Novel treatment concepts based on these molecular alterations are currently being addressed in clinical trials and will lead to an enhanced implementation of precision medicine strategies.

Systematic analysis reveals molecular characteristics of ERG-negative prostate cancer

The TMPRSS2:ERG gene fusion is the most prevalent early driver gene activation in prostate cancers of European ancestry, while the fusion frequency is much lower in Africans and Asians. The genomic characteristics and mechanisms for patients lacking ERG fusion are still unclear. In this study, we systematically compared the characteristics of gene fusions, somatic mutations, copy number alterations and gene expression signatures between 201 ERG fusion positive and 296 ERG fusion negative prostate cancer samples. Both common and group-specific genomic alterations were observed, suggesting shared and different mechanisms of carcinogenesis in prostate cancer samples with or without ERG fusion. The genomic alteration patterns detected in ERG-negative group showed similarities with 77.5% of tumor samples of African American patients. These results emphasize that genomic and gene expression features of the ERG-negative group may provide a reference for populations with lower ERG fusion frequency. While the overall expression patterns were comparable between ERG-negative and ERG-positive tumors, we found that genomic alterations could affect the same pathway through distinct genes in the same pathway in both groups of tumor types. Altogether, the genomic and molecular characteristics revealed in our study may provide new opportunities for molecular stratification of ERG-negative prostate cancers.

Differential expression of Annexin 2, SPINK1, and Hsp60 predict progression of prostate cancer through bifurcated WHO Gleason score categories in African American men

BACKGROUND

Although studies have observed several markers correlate with progression of prostate cancer (PCa), no specific markers have been identified that accurately predict the progression of this disease, even in African American (AA) men who are generally at higher risk than other ethnic groups. The primary goal of this study was to explore whether three markers could predict the progression of PCa.

METHOD

We investigated protein expression of Annexin 2 (ANX2), serine peptidase inhibitor, kazal type 1(SPINK1)/tumor-associated trypsin inhibitor (TATI), and heat shock protein 60 (Hsp60) in 79 archival human prostate trans-rectal ultrasound (TRUS) biopsy tissues according to a modified World Health Organization (WHO) classification: normal (WHO1a), Gleason Score (GS6 (WHO1b), GS7 subgroups (WHO2 = 3 + 4, WHO3 = 4 + 3), GS8 (WHO4), and GS9-10 (WHO5). AA men aged 41-90 diagnosed from 1990 to 2013 at Howard University were included. Automated staining assessed expression of each biomarker. Spearman correlation assessed the direction and relationship between biomarkers, WHO and modified WHO GS, age, and 5-year survival. A two-tailed t-test and ANOVA evaluated biomarkers expression in relationship to WHO normal and other GS levels, and between WHO GS levels. A logistic and linear regression analysis examined the relationship between biomarker score and WHO GS categories. Kaplan-Meier curves graphed survival.

RESULTS

ANX2 expression decreased monotonically with the progression of PCa while expression of SPINK1/TATI and Hsp60 increased but had a more WHO GS-specific effect; SPINK1/TATI differed between normal and GS 2-6 and HSP60 differed between GS 7 and GS 2-6. WHO GS was found to be significantly and negatively associated with ANX2, and positively with SPINK1/TATI and Hsp60 expression. High SPINK1/TATI expression together with the low ANX2 expression at higher GS exhibited a bi-directional relationship that is associated with PCa progression and survival.

CONCLUSION

Importantly, the data reveal that ANX2, and SPINK1/TAT1 highly associate with WHO GS and with the transition from one stage of PrCa to the next in AA men. Future research is needed in biracial and larger population studies to confirm this dynamic relationship between ANX2 and SPINK1 as independent predictors of PCa progression in all men.

Impact of the SPOP Mutant Subtype on the Interpretation of Clinical Parameters in Prostate Cancer

Purpose

Molecular characterization of prostate cancer, including The Cancer Genome Atlas, has revealed distinct subtypes with underlying genomic alterations. One of these core subtypes, SPOP (speckle-type POZ protein) mutant prostate cancer, has previously only been identifiable via DNA sequencing, which has made the impact on prognosis and routinely used risk stratification parameters unclear.

Methods

We have developed a novel gene expression signature, classifier (Subclass Predictor Based on Transcriptional Data), and decision tree to predict the SPOP mutant subclass from RNA gene expression data and classify common prostate cancer molecular subtypes. We then validated and further interrogated the association of prostate cancer molecular subtypes with pathologic and clinical outcomes in retrospective and prospective cohorts of 8,158 patients.

Results

The subclass predictor based on transcriptional data model showed high sensitivity and specificity in multiple cohorts across both RNA sequencing and microarray gene expression platforms. We predicted approximately 8% to 9% of cases to be SPOP mutant from both retrospective and prospective cohorts. We found that the SPOP mutant subclass was associated with lower frequency of positive margins, extraprostatic extension, and seminal vesicle invasion at prostatectomy; however, SPOP mutant cancers were associated with higher pretreatment serum prostate-specific antigen (PSA). The association between SPOP mutant status and higher PSA level was validated in three independent cohorts. Despite high pretreatment PSA, the SPOP mutant subtype was associated with a favorable prognosis with improved metastasis-free survival, particularly in patients with high-risk preoperative PSA levels.

Conclusion

Using a novel gene expression model and a decision tree algorithm to define prostate cancer molecular subclasses, we found that the SPOP mutant subclass is associated with higher preoperative PSA, less adverse pathologic features, and favorable prognosis. These findings suggest a paradigm in which the interpretation of common risk stratification parameters, particularly PSA, may be influenced by the underlying molecular subtype of prostate cancer.

Prostate cancer with cribriform morphology: diagnosis, aggressiveness, molecular pathology and possible relationships with intraductal carcinoma

INTRODUCTION

The Gleason grading system is one of the most important prognostic factors in prostate cancer (PCa). From the 2005 to the 2014 conference organized by the International Society of Urological Pathology (ISUP), the histological criteria for the Gleason patterns were improved, resulting in the shrinkage of the Gleason pattern (GP) 3 and expansion of the GP 4. Areas Covered: Cribriform, fused, ill-defined and glomeruloid glands are part of the morphologic spectrum of the current GP 4. Cribriform, derived from the Latin word cribrum (i.e. sieve), was introduced by Gleason to describe glands composed of a solid sheet with perforations or lumina. Cribriform morphology has a worse prognosis compared with the other, non-cribriform, GP4 morphologies. A practical implication is that a cribriform growth precludes a patient from selecting an active surveillance (AS) protocol. Expert commentary: The presence of these four growth patterns should be incorporated into the current Grade Group (GG) system. Enhancing our understanding of cribriform tumor behavior will lead to correctly identifying and treating those patients that will die because of PCa, while sparing treatment in those who do not require it.

Molecular alterations associated with prostate cancer

Introduction

The amount of information and knowledge about pathways and genetic alterations regarding prostate cancer, including the tools available for its study has been recently increasing. Additionally, a variety of molecular signaling pathways control cell proliferation, however, this incompletely understood process is disturbed in cancer cells.

Materials and methods

A literature review was made using the MEDLINE, Embase and LILACS databases searching for the following keywords: prostate neoplasms, prostate cancer, molecular medicine, genomics, pathways, and cell cycle.

Results

Different biological mechanisms have been associated with the development of prostate cancer, such as alterations in tumor suppressor genes, oncogenes (TP53, RB1, among others) and CDKIs; DNA methylation; chromosomal alterations and rearrangements; changes in PTEN and PI3K / mTOR; global defects in apoptosis; alterations in the androgen receptor (AR); and epigenetic mechanisms.

Conclusions

Good clinical practice and a practical approach have to be based on basic knowledge, thus, in this article, the main genetic alterations, mutations and pathways involved in prostate cancer development were reviewed.

[Neuroendocrine prostate cancer: Natural history, molecular features, therapeutic management and future directions]

Neuroendocrine prostate cancer is a rare malignancy with a an adverse prognostic. Histologically, It can be pure (small cells or large cells neuroendocrine carcinoma) or mixed with a adenocarcinoma component. Rarely diagnosed de novo, neuroendocrine prostate cancer is generally associated with advanced stage disease resistant to castration. As such, this histological subtype could represent an aggressive evolution of prostatic adenocarcinoma, through the epithelio-neuroendocrine transdifferentiation mechanism (phenomenon of lineage plasticity). Nonetheless, neuroendocrine prostate cancer is a heterogeneous malignancy with multiple histopathological variants showing distinct clinical features. The broad variety of molecular analyses could help to understand the ontogeny of this histological subtype and its signaling pathways. This may also allow identifying diagnostic and prognostic biomarkers as well as potential molecular targets. However, treatment options are currently limited and consist only in platinium-based chemotherapy for advanced stage disease.

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.

Stem cells and the role of ETS transcription factors in the differentiation hierarchy of normal and malignant prostate epithelium

Prostate cancer is the most common cancer of men in the UK and accounts for a quarter of all new cases. Although treatment of localised cancer can be successful, there is no cure for patients presenting with invasive prostate cancer and there are less treatment options. They are generally treated with androgen-ablation therapies but eventually the tumours become hormone resistant and patients develop castration-resistant prostate cancer (CRPC) for which there are no further successful or curative treatments. This highlights the need for new treatment strategies. In order to prevent prostate cancer recurrence and treatment resistance, all the cell populations in a heterogeneous prostate tumour must be targeted, including the rare cancer stem cell (CSC) population. The ETS transcription factor family members are now recognised as a common feature in multiple cancers including prostate cancer; with aberrant expression, loss of tumour suppressor function, inactivating mutations and the formation of fusion genes observed. Most notably, the TMPRSS2-ERG gene fusion is present in approximately 50% of prostate cancers and in prostate CSCs. However, the role of other ETS transcription factors in prostate cancer is less well understood. This review will describe the prostate epithelial cell hierarchy and discuss the evidence behind prostate CSCs and their inherent resistance to conventional cancer therapies. The known and proposed roles of the ETS family of transcription factors in prostate epithelial cell differentiation and regulation of the CSC phenotype will be discussed, as well as how they might be targeted for therapy.

Micro-RNA-204 Participates in TMPRSS2/ERG Regulation and Androgen Receptor Reprogramming in Prostate Cancer

Cancer progression is driven by genome instability incurred rearrangements such as transmembrane protease, serine 2 (TMPRSS2)/v-ets erythroblastosis virus E26 oncogene (ERG) that could possibly turn some of the tumor suppressor micro-RNAs into pro-oncogenic ones. Previously, we found dualistic miR-204 effects, acting either as a tumor suppressor or as an oncomiR in ERG fusion-dependent manner. Here, we provided further evidence for an important role of miR-204 for TMPRSS2/ERG and androgen receptor (AR) signaling modulation and fine tuning that prevents TMPRSS2/ERG overexpression in prostate cancer. Based on proximity-based ligation assay, we designed a novel method for detection of TMPRSS2/ERG protein products. We found that miR-204 is TMPRSS2/ERG oncofusion negative regulator, and this was mediated by DNA methylation of TMPRSS2 promoter. Transcriptional factors runt-related transcription factor 2 (RUNX2) and ETS proto-oncogene 1 (ETS1) were positive regulators of TMPRSS2/ERG expression and promoter hypo-methylation. Clustering of patients' sera for fusion protein, transcript expression, and wild-type ERG transcript isoforms, demonstrated not all patients harboring fusion transcripts had fusion protein products, and only few fusion positive ones exhibited increased wild-type ERG transcripts. miR-204 upregulated AR through direct promoter hypo-methylation, potentiated by the presence of ERG fusion and RUNX2 and ETS1. Proteomics studies provided evidence that miR-204 has dualistic role in AR cancer-related reprogramming, promoting prostate cancer-related androgen-responsive genes and AR target genes, as well as AR co-regulatory molecules. miR-204 methylation regulation was supported by changes in molecules responsible for chromatin remodeling, DNA methylation, and its regulation. In summary, miR-204 is a mild regulator of the AR function during the phase of preserved AR sensitivity as the latter one is required for ERG-fusion translocation.

Prostate Cancer Genetics: Variation by Race, Ethnicity, and Geography

Prostate cancer rates vary substantially by race, ethnicity, and geography. These disparities can be explained by variation in access to screening and treatment, variation in exposure to prostate cancer risk factors, and variation in the underlying biology of prostate carcinogenesis (including genomic propensity of some groups to develop biologically aggressive disease). It is clear that access to screening and access to treatment are critical influencing factors of prostate cancer rates; yet, even among geographically diverse populations with similar access to care (eg, low- and medium-income countries), African descent men have higher prostate cancer rates and poorer prognosis. To date, the proportion of prostate cancer that can be explained by environmental exposures is small, and the effect of these factors across different racial, ethnic, or geographical populations is poorly understood. In contrast, prostate cancer has one of the highest heritabilities of all major cancers. Numerous genetic susceptibility markers have been identified from family-based studies, candidate gene association studies, and genome-wide association studies. Some prostate cancer loci, including the risk loci found at chromosome 8q24, have consistent effects in all groups studied to date. However, replication of many susceptibility loci across race, ethnicity, and geography remains limited, and additional studies in certain populations (particularly in men of African descent) are needed to better understand the underlying genetic basis of prostate cancer.

Characterizing the molecular features of ERG-positive tumors in primary and castration resistant prostate cancer

BACKGROUND

The TMPRSS2-ERG gene fusion is detected in approximately half of primary prostate cancers (PCa) yet the prognostic significance remains unclear. We hypothesized that ERG promotes the expression of common genes in primary PCa and metastatic castration-resistant PCa (CRPC), with the objective of identifying ERG-associated pathways, which may promote the transition from primary PCa to CRPC.

METHODS

We constructed tissue microarrays (TMA) from 127 radical prostatectomy specimens, 20 LuCaP patient-derived xenografts (PDX), and 152 CRPC metastases obtained immediately at time of death. Nuclear ERG was assessed by immunohistochemistry (IHC). To characterize the molecular features of ERG-expressing PCa, a subset of IHC confirmed ERG+ or ERG- specimens including 11 radical prostatectomies, 20 LuCaP PDXs, and 45 CRPC metastases underwent gene expression analysis. Genes were ranked based on expression in primary PCa and CRPC. Common genes of interest were targeted for IHC analysis and expression compared with biochemical recurrence (BCR) status.

RESULTS

IHC revealed that 43% of primary PCa, 35% of the LuCaP PDXs, and 18% of the CRPC metastases were ERG+ (12 of 48 patients [25%] had at least one ERG+ metastasis). Based on gene expression data and previous literature, two proteins involved in calcium signaling (NCALD, CACNA1D), a protein involved in inflammation (HLA-DMB), CD3 positive immune cells, and a novel ERG-associated protein, DCLK1 were evaluated in primary PCa and CRPC metastases. In ERG+ primary PCa, a weak association was seen with NCALD and CACNA1D protein expression. HLA-DMB association with ERG was decreased and CD3 cell number association with ERG was changed from positive to negative in CRPC metastases compared to primary PCa. DCLK1 was upregulated at the protein level in unpaired ERG+ primary PCa and CRPC metastases (P = 0.0013 and P < 0.0001, respectively). In primary PCa, ERG status or expression of targeted proteins was not associated with BCR-free survival. However, for primary PCa, ERG+DCLK1+ patients exhibited shorter time to BCR (P = 0.06) compared with ERG+DCLK1- patients.

CONCLUSIONS

This study examined ERG expression in primary PCa and CRPC. We have identified altered levels of inflammatory mediators associated with ERG expression. We determined expression of DCLK1 correlates with ERG expression and may play a role in primary PCa progression to metastatic CPRC. Prostate 76:810-822, 2016. © 2016 Wiley Periodicals, Inc.

Concurrent TMPRSS2-ERG and SLC45A3-ERG rearrangements plus PTEN loss are not found in low grade prostate cancer and define an aggressive tumor subset

BACKGROUND

SLC45A3 is the second most common ERG partner in prostate cancer (PrCa). Coexisting TMPRSS2 and SLC45A3 rearrangements are found in a subset of cases, but the meaning is still unknown.

METHODS

SLC45A3-ERG and TMPRSS2-ERG rearrangements and their association with ERG and PTEN expression and with clinical and pathological features have been analyzed in 80 PrCa (PSMAR-Biobank, Barcelona, Spain). ERG and PTEN mRNA were assessed by qRT-PCR; TMPRSS2-ERG and SLC45A3-ERG by RT-PCR, FISH, and direct sequencing; and ERG expression by IHC. The endpoints were Gleason score (GS), stage, and PSA progression-free survival.

RESULTS

Single TMPRSS2-ERG was found in 51.6% GS ≤ 7 and 22.2% GS ≥ 8 tumors (P = 0.027). SLC45A3-ERG was found in 25 cases, 20 of them with concurrent TMPRSS2-ERG rearrangement: 11.5% GS = 6, 22.2% GS = 7, and 50% GS ≥ 8 tumors (P = 0.013). Double rearrangements were associated with higher levels of ERG mRNA (P = 0.04). Double rearrangement plus PTEN loss was detected in 0% GS = 6; 14.7% GS = 7, and 29.4% GS ≥ 8 tumors (P = 0.032). Furthermore, this triple change was present in 19.2% stage T3-4 but not in any of stage T2 tumors (P = 0.05). No relationship was found with PSA progression-free survival.

CONCLUSIONS

Single TMPRSS2-ERG translocation is associated with low grade PrCa. Subsequent development of SLC45A3-ERG results in higher ERG expression. The combination of double rearrangement plus PTEN loss, according to our series, is never found in low grade, low stage tumors. These findings could be potentially useful in therapeutic decision making in PrCa. Tumors with combined TMPRSS2-ERG/SLC45A3-ERG fusions plus PTEN loss should be excluded from watchful waiting and are candidates for intensive therapy. Prostate 76:854-865, 2016. © 2016 Wiley Periodicals, Inc.

ERG Expression in Prostate Needle Biopsy: Potential Diagnostic and Prognostic Implications

To investigate the prognostic and diagnostic value of ERG immunohistochemistry (IHC) in prostate needle biopsy when combined with AMACR-CK5/6. ERG IHC was assessed in 119 consecutive prostate needle biopsies where the dual-stain AMACR-CK5/6 IHC was ordered and in 16 cases with a Gleason score (GS) ≥7. IHC results were evaluated in prostate carcinoma (PCA), high-grade prostatic intraepithelial neoplasia (HGPIN), HGPIN with adjacent atypical glands (PINATYP), atypical/suspicious (ASAP) foci, and benign PCA mimickers. GS, HGPIN, extraprostatic extension, perineural invasion, bilateralism of PCA, largest percent of core, and the overall percent of tissue involved by PCA were recorded. ERG was detected in 36% of PCA, 27% of HGPIN, 13% of ATYP/PINATYP, and none of benign mimickers. ERG-positive HGPIN was strongly associated with ERG-positive PCA in the same core compared with ERG-negative HGPIN (P<0.0001). Positive ERG expression in PCA was inversely related to GS and showed trends toward association with higher volume and bilateral disease. ERG was more specific for PCA than AMACR (0.87 vs. 0.23), but less sensitive (0.36 vs. 0.95). In conclusion, ERG IHC is of limited additional diagnostic value when added to AMACR and CK5/6. ERG expression is inversely related to GS and is associated with bilateral involvement and higher PCA tumor volume. ERG-positive HGPIN is strongly associated with the presence of PCA in the same core. Studies investigating the prognostic value of ERG in HGPIN should be implemented to address whether patients with ERG-positive HGPIN are at increased risk for subsequent PCA development.

Novel Biomarker Signature That May Predict Aggressive Disease in African American Men With Prostate Cancer

PURPOSE

We studied the ethnicity-specific expression of prostate cancer (PC) -associated biomarkers to evaluate whether genetic/biologic factors affect ethnic disparities in PC pathogenesis and disease progression.

PATIENTS AND METHODS

A total of 154 African American (AA) and 243 European American (EA) patients from four medical centers were matched according to the Cancer of the Prostate Risk Assessment postsurgical score within each institution. The distribution of mRNA expression levels of 20 validated biomarkers reported to be associated with PC initiation and progression was compared with ethnicity using false discovery rate, adjusted Wilcoxon-Mann-Whitney, and logistic regression models. A conditional logistic regression model was used to evaluate the interaction between ethnicity and biomarkers for predicting clinicopathologic outcomes.

RESULTS

Of the 20 biomarkers examined, six showed statistically significant differential expression in AA compared with EA men in one or more statistical models. These include ERG (P < .001), AMACR (P < .001), SPINK1 (P = .001), NKX3-1 (P = .03), GOLM1 (P = .03), and androgen receptor (P = .04). Dysregulation of AMACR (P = .036), ERG (P = .036), FOXP1 (P = .041), and GSTP1 (P = .049) as well as loss-of-function mutations for tumor suppressors NKX3-1 (P = .025) and RB1 (P = .037) predicted risk of pathologic T3 disease in an ethnicity-dependent manner. Dysregulation of GOLM1 (P = .037), SRD5A2 (P = .023), and MKi67 (P = .023) predicted clinical outcomes, including 3-year biochemical recurrence and metastasis at 5 years. A greater proportion of AA men than EA men had triple-negative (ERG-negative/ETS-negative/SPINK1-negative) disease (51% v 35%; P = .002).

CONCLUSION

We have identified a subset of PC biomarkers that predict the risk of clinicopathologic outcomes in an ethnicity-dependent manner. These biomarkers may explain in part the biologic contribution to ethnic disparity in PC outcomes between EA and AA men.

Association of ERG and TMPRSS2-ERG with grade, stage, and prognosis of prostate cancer is dependent on their expression levels

BACKGROUND

There is controversy in the literature on the role of the fusion TMPRSS2-ERG in the pathogenesis and progression of prostate cancer. The quantitative differences in TMPRSS2-ERG fusion expression have received very limited attention in the literature.

METHODS

We have quantitatively analyzed the mRNA levels of TMPRSS2-ERG, ERG, PTEN, and AR (n = 83), as well as ERG immunostaining (n = 78) in a series of prostate tumors.

RESULTS

Among the TMPRSS2-ERG cases (n = 57), high fusion levels were associated with GS ≥8 (P = 0.025). ERG mRNA overexpression was associated with GS ≥8 (P = 0.047), and with stage T3-T4 tumors (P = 0.032). Among the ERG overexpressing cases (n = 54), higher expression levels were found in 92.3% of GS ≥8 tumors (P = 0.02). ERG immunostaining, regardless of staining intensity, was also associated with high stage (P = 0.05). There was a statistical association between ERG immunostaining and PSA progression-free survival (Log Rank test, P = 0.048). Decreased PTEN expression was associated with TMPRSS2-ERG (P = 0.01), ERG mRNA overexpression (P = 0.003) and ERG immunostaining (P = 0.007). Furthermore, decreased PTEN expression, alone (P = 0.041) and also combined with TMPRSS2-ERG (P = 0.04) or with ERG overexpression (P = 0.04) was associated with GS ≥7 tumors.

CONCLUSIONS

Although more studies are needed to further clarify their role, our findings emphasize that the expression levels of the TMPRSS2-ERG fusion and ERG mRNA, rather than their mere presence, are related to a more aggressive phenotype, have an effect on prognosis and could be molecular markers of progression for prostate cancer. Furthermore, ERG immunohistochemistry could be also a potentially useful prognostic factor.

A multicenter study shows PTEN deletion is strongly associated with seminal vesicle involvement and extracapsular extension in localized prostate cancer

BACKGROUND

Loss of the phosphatase and tensin homolog (PTEN) tumor suppressor gene is a promising marker of aggressive prostate cancer. Active surveillance and watchful waiting are increasingly recommended to patients with small tumors felt to be low risk, highlighting the difficulties of Gleason scoring in this setting. There is an urgent need for predictive biomarkers that can be rapidly deployed to aid in clinical decision-making. Our objectives were to assess the incidence and ability of PTEN alterations to predict aggressive disease in a multicenter study.

METHODS

We used recently developed probes optimized for sensitivity and specificity in a four-color FISH deletion assay to study the Canary Retrospective multicenter Prostate Cancer Tissue Microarray (TMA). This TMA was constructed specifically for biomarker validation from radical prostatectomy specimens, and is accompanied by detailed clinical information with long-term follow-up.

RESULTS

In 612 prostate cancers, the overall rate of PTEN deletion was 112 (18.3%). Hemizygous PTEN losses were present in 55/612 (9.0%) of cancers, whereas homozygous PTEN deletion was observed in 57/612 (9.3%) of tumors. Significant associations were found between PTEN status and pathologic stage (P < 0.0001), seminal vesicle invasion (P = 0.0008), extracapsular extension (P < 0.0001), and Gleason score (P = 0.0002). In logistic regression analysis of clinical and pathological variables, PTEN deletion was significantly associated with extracapsular extension, seminal vesicle involvement, and higher Gleason score. In the 406 patients in which clinical information was available, PTEN homozygous (P = 0.009) deletion was associated with worse post-operative recurrence-free survival (number of events = 189), pre-operative prostate specific antigen (PSA) (P < 0.001), and pathologic stage (P = 0.03).

CONCLUSION

PTEN status assessed by FISH is an independent predictor for recurrence-free survival in multivariate models, as were seminal vesicle invasion, extracapsular extension, and Gleason score, and preoperative PSA. Furthermore, these data demonstrate that the assay can be readily introduced at first diagnosis in a cost effective manner analogous to the use of FISH for analysis of HER2/neu status in breast cancer. Combined with published research beginning 17 years ago, both the data and tools now exist to implement a PTEN assay in the clinic.

The oncogene ERG: a key factor in prostate cancer

ETS-related gene (ERG) is a member of the E-26 transformation-specific (ETS) family of transcription factors with roles in development that include vasculogenesis, angiogenesis, haematopoiesis and bone development. ERG's oncogenic potential is well known because of its involvement in Ewing's sarcoma and leukaemia. However, in the past decade ERG has become highly associated with prostate cancer development, particularly as a result of a gene fusion with the promoter region of the androgen-induced TMPRRSS2 gene. We review ERG's structure and function, and its role in prostate cancer. We discuss potential new therapies that are based on targeting ERG.

Reconstitution of the ERG Gene Expression Network Reveals New Biomarkers and Therapeutic Targets in ERG Positive Prostate Tumors

BACKGROUND

Despite a growing number of studies evaluating cancer of prostate (CaP) specific gene alterations, oncogenic activation of the ETS Related Gene (ERG) by gene fusions remains the most validated cancer gene alteration in CaP. Prevalent gene fusions have been described between the ERG gene and promoter upstream sequences of androgen-inducible genes, predominantly TMPRSS2 (transmembrane protease serine 2). Despite the extensive evaluations of ERG genomic rearrangements, fusion transcripts and the ERG oncoprotein, the prognostic value of ERG remains to be better understood. Using gene expression dataset from matched prostate tumor and normal epithelial cells from an 80 GeneChip experiment examining 40 tumors and their matching normal pairs in 40 patients with known ERG status, we conducted a cancer signaling-focused functional analysis of prostatic carcinoma representing moderate and aggressive cancers stratified by ERG expression.

RESULTS

In the present study of matched pairs of laser capture microdissected normal epithelial cells and well-to-moderately differentiated tumor epithelial cells with known ERG gene expression status from 20 patients with localized prostate cancer, we have discovered novel ERG associated biochemical networks.

CONCLUSIONS

Using causal network reconstruction methods, we have identified three major signaling pathways related to MAPK/PI3K cascade that may indeed contribute synergistically to the ERG dependent tumor development. Moreover, the key components of these pathways have potential as biomarkers and therapeutic target for ERG positive prostate tumors.

Next-generation sequencing technology in prostate cancer diagnosis, prognosis, and personalized treatment

Next-generation sequencing (NGS) of the genetic information of cancer cells has revolutionized the field of cancer biology, including prostate cancer (PCa). New recurrent alterations have been identified in PCa (e.g., TMPRSS2-ERG translocation, SPOP and CHD1 mutations, and chromoplexy), and many previous ones in well-established pathways have been validated (e.g., androgen receptor overexpression and mutations; PTEN, RB1, and TP53 loss/mutations). With its highly heterogeneous nature, PCa continues to pose a tremendous challenge in terms of diagnosis and prognosis. Combining the information gained through NGS studies with clinicopathological and radiological data will help diagnose the aggressiveness of the cancer with greater accuracy. Furthermore, understanding the heterogeneity of tumor through single-cell or single-molecule sequencing technology will also strengthen the prognosis and provide better, patient-specific drug identification. As this research becomes more prominent, it is important that urologic oncologists become familiar with the various NGS technologies and the results generated using them. We highlight the commonly used NGS tools and summarize recent discoveries relevant to PCa.

Prevalence and prognostic significance of TMPRSS2-ERG gene fusion in lymph node positive prostate cancers

BACKGROUND

TMPRSS2-ERG gene fusion is the most frequent genetic alteration in prostate cancer. However, information about its distribution in lymph node positive prostate cancers and the prognostic significance in these advanced tumors is unknown.

METHODS

Gene fusion status was determined by fluorescence in situ hybridization on a tissue-microarray constructed from 119 hormone-naïve nodal positive, surgically treated prostate cancers containing samples from the primary tumors and corresponding lymph node metastases. Data were correlated with various tumor features (Gleason score, stage, cancer volume, nodal tumor burden) and biochemical recurrence-free, disease-specific, and overall survival.

RESULTS

TMPRSS2-ERG fusion was detected in 43.5% of the primary tumors. Conversely, only 29.9% of the metastasizing components showed the fusion. Concordance in TMPRSS2-ERG status between primary tumors and metastases was 70.9% (Kappa 0.39); 20.9% and 8.1% of the patients showed the mutation solely in their primary tumors and metastases, respectively. TMPRSS2-ERG fusion was not correlated with specific histopathological tumor features but predicted favorable biochemical recurrence-free, disease-specific and overall survival independently when present in the primary tumor (P < 0.05 each).

CONCLUSION

TMPRSS2-ERG fusion is more frequent in primary prostate cancer than in corresponding metastases suggesting no selection of fusion-positive cells in the metastatic process. The gene fusion in primary tumors independently predicts favorable outcome.

Biomarkers and personalized risk stratification for patients with clinically localized prostate cancer

Prostate cancer (PCa) is the most common neoplasia among men in developed countries and a leading cause of cancer-related morbidity and mortality. PCa is a very heterogeneous disease, both clinically and biologically. Currently, it is difficult to stratify patients into risk groups that entail different disease management. Therefore, a personalized view of this disease is mandatory, through the development of new and more accurate biomarkers that may help clinicians to stratify patients according to threat that PCa poses for each patient. Hence, this review focuses on recent developments of molecular and immunohistochemical biomarkers for PCa risk stratification that might enable a personalized approach to PCa patients. However, despite the increasing amount of available data, there is also an urgent need to translate the most promising biomarkers for clinical use through large multicenter validation trials. Ultimately, these will contribute for an improved clinical management of PCa patients.

New concepts concerning prostate cancer screening

Prostate Cancer (CaP) is rapidly becoming a worldwide health issue. While CaP mortality has decreased in recent years, coincident with the widespread use of Prostate-Specific Antigen (PSA) screening, it remains the most common solid tumor in men and is the second leading cause of cancer death in the United States. The frequency of CaP is growing not only in western cultures, but also its incidence is dramatically increasing in eastern nations. Recently, examination of data from long-term trials and follow up has cast a shadow on the effectiveness of employing PSA as a primary screening tool for CaP. In this review, we not only summarize opinions from this examination and synthesize recommendations from several groups that suggest strategies for utilizing PSA as a tool, but also call for research into biomarkers for CaP diagnosis and disease progression. We also describe our recent work that identified a smooth muscle contractile protein in prostate epithelia, namely smooth muscle gamma actin, and indicate the potential for this molecule as a new unique footprint and as a CaP marker.

Androgen receptor gene rearrangements: new perspectives on prostate cancer progression

The androgen receptor (AR) is a master regulator transcription factor in normal and cancerous prostate cells. Canonical AR activation requires binding of androgen ligand to the AR ligand binding domain, translocation to the nucleus, and transcriptional activation of AR target genes. This regulatory axis is targeted for systemic therapy of advanced prostate cancer. However, a new paradigm for AR activation in castration-resistant prostate cancer (CRPC) has emerged wherein alternative splicing of AR mRNA promotes synthesis of constitutively active AR variants that lack the AR ligand binding domain (LBD). Recent work has indicated that structural alteration of the AR gene locus represents a key mechanism by which alterations in AR mRNA splicing arise. In this review, we examine the role of truncated AR variants (ARVs) and their corresponding genomic origins in models of prostate cancer progression, as well as the challenges they pose to the current standard of prostate cancer therapies targeting the AR ligand binding domain. Since ARVs lack the COOH-terminal LBD, the genesis of these AR gene rearrangements and their resulting ARVs provides strong rationale for the pursuit of new avenues of therapeutic intervention targeted at the AR NH2-terminal domain. We further suggest that genomic events leading to ARV expression could act as novel biomarkers of disease progression that may guide the optimal use of current and next-generation AR-targeted therapy.

ERG rearrangement and protein expression in the progression to castration-resistant prostate cancer

BACKGROUND

Approximately half of the prostate carcinomas are characterized by a chromosomal rearrangement fusing the androgen-regulated gene TMPRSS2 to the oncogenic ETS transcription factor ERG. Aim of this study was to comprehensively analyze the role and impact of the ERG rearrangement and protein expression on the progression to castration-resistant (CR) disease.

METHODS

We used a tissue microarray (TMA) constructed from 114 hormone naive (HN) and 117 CR PCs. We analyzed the ERG rearrangement status by fluorescence in situ hybridization and the expression profiles of ERG, androgen receptor (AR) and the proliferation marker Ki67 by immunohistochemistry.

RESULTS

Nearly half of the PC tissue specimens (HN: 38%, CR: 46%) harbored a TMPRSS2-ERG gene fusion. HN PCs with positive translocation status showed increased tumor cell proliferation (P<0.05). As expected, TMPRSS2-ERG gene fusion was strongly associated with increased ERG protein expression in HN and CR PCs (both P<0.0001). Remarkably, the study revealed a subgroup (26%) of CR PCs with ERG rearrangement but without any detectable ERG protein expression. This subgroup showed significantly lower levels of AR protein expression and androgen-regulated serum PSA (both P<0.05).

CONCLUSIONS

In this study, we identified a subgroup of ERG-rearranged CR PCs without detectable ERG protein expression. Our results suggest that this subgroup could represent CR PCs with a dispensed AR pathway. These tumors might represent a thus far unrecognized subset of patients with AR-independent CR PC who may not benefit from conventional therapy directed against the AR pathway.

Genetic profiling to determine risk of relapse-free survival in high-risk localized prostate cancer

PURPOSE

The characterization of actionable mutations in human tumors is a prerequisite for the development of individualized, targeted therapy. We examined the prevalence of potentially therapeutically actionable mutations in patients with high-risk clinically localized prostate cancer.

EXPERIMENTAL DESIGN

Forty-eight samples of formalin-fixed paraffin-embedded prostatectomy tissue from a neoadjuvant chemotherapy trial were analyzed. DNA extracted from microdissected tumor was analyzed for 643 common solid tumor mutations in 53 genes using mass spectroscopy-based sequencing. In addition, PTEN loss and erythroblast transformation-specific-related gene (ERC) translocations were examined using immunohistochemistry (IHC) in associated tissue microarrays. Association with relapse during 5 years of follow-up was examined in exploratory analyses of the potential clinical relevance of the genetic alterations.

RESULTS

Of the 40 tumors evaluable for mutations, 10% had point mutations in potentially actionable cancer genes. Of the 47 tumors evaluable for IHC, 36% had PTEN loss and 40% had ERG rearrangement. Individual mutations were not frequent enough to determine associations with relapse. Using Kaplan-Meier analysis with a log-rank test, the 16 patients who had PTEN loss had a significantly shorter median relapse-free survival, 19 versus 106 months (P = 0.01).

CONCLUSIONS

This study confirms that point mutations in the most common cancer regulatory genes in prostate cancer are rare. However, the PIK3CA/AKT pathway was mutated in 10% of our samples. Although point mutations alone did not have a statistically significant association with relapse, PTEN loss was associated with an increased relapse in high-risk prostate cancer treated with chemotherapy followed by surgery.