ERG Fusion Research Articles

Ductal (PDC), acinar (PAC) and neuroendocrine (PNC) carcinomas of the prostate: A comparative comprehensive genomic profiling (CGP) study.

5064 Background: PDC, PAC and PNC are histologic subtypes of prostate cancer (PC). We queried whether these subsets would share similar genomic alterations (GA) reflecting their disease biology and clinical features. Methods: CGP was performed using a hybrid capture-based assay on 61 PDC, 4,132 PAC and 217 PNC. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Results: The age, GA per tumor and TP53 GA of PDC, PAC and PNC were similar (Table). RB1 GA were predominant in PNC. TMPRSS2:ERG fusions were most frequent in PNC, intermediate in PAC and lowest in PDC. AR GA were more often identified in PAC than PDC or PNC whereas PTEN GA were most frequent in PDC than PAC or PNC. Targetable GA were identified in all 3 groups when focused on BRCA2 (PARP inhibitors) and PIK3CA (MTOR inhibitors). ATM GA (PARP inhibitors) were more common in PAC than PDC or PNC. BRAF GA (BRAF/MEK inhibitors) were more frequent in PDC and PAC than PNC. CDK12 GA potentially associated with immunotherapy (IO) benefit were similar in PDC and PAC and low in PNC. Low frequencies of MSI-High and low median TMB levels were similar in all 3 groups. Conclusions: The pathologic features of PDC, PAC and PNC have been classically maintained as representative of 3 different tumor types with potentially contrasting histogenesis. In the current CGP based study, all 3 tumor types did not display significant differences in genomic signatures other than the high RB1 GA. CGP may reveal biomarkers that could direct patients to targeted (PARP, MTOR and BRAF/MEK inhibitors) or immunotherapies ( CDK12 GA, MSI-High or high TMB status) especially in PDC and PAC. [Table: see text]

SPOP and FOXA1 mutations are associated with PSA recurrence in ERG wt tumors, and SPOP downregulation with ERG-rearranged prostate cancer.

ERG fusion-related prostate cancer (PrCa) is the most prevalent oncogenic driver subclass. SPOP, FOXA1, and IDH1 mutations are other three main oncogenic driver subclasses in non-ETS-fusion PrCa. ERG protein levels seem to be increased in SPOP-mutated cases, and different studies reported that SPOP mutations and ERG fusions are mutually exclusive. The aim of this study has been to analyze the alterations in non-ETS-oncogenic drivers in PrCa. SPOP, FOXA1, and IDH mutations were investigated by polymerase chain reaction (PCR) and Sanger direct sequencing. ERG, SPOP, and TMPRSS2-ERG messenger RNA expression was assessed by quantitative real-time PCR from complementary DNA, and the presence of the fusion was also analyzed by nonquantitative PCR. The clinical pathological features were retrieved from the charts of the 111 patients included in the study (MARBiobanc, Barcelona, Spain). Loss of SPOP expression (25.2%) was associated with ERG overexpression (P = 0.0036). SPOP mutations were found in 5.4% cases, all with wild-type (wt) ERG (P = 0.007). FOXA1 mutations were found in 8.2% cases, most of them ERG wt (P = 0.06). No IDH1 mutations were found. SPOP or FOXA1 mutations were found in 1.7% of ERG-rearranged, and 34.2% of non-ERG-rearranged cases (P < 0.0001). SPOP or FOXA1 alterations (mutations or expression loss) were significantly more common in GG5, while isolated ERG overexpression was more common in GG1 tumors (P = 0.042). SPOP-or FOXA1-mutated cases were associated with a shorter time to prostate-specific antigen (PSA) recurrence in the univariate (P = 0.0009), and with the PSA recurrence risk in the multivariate (P = 0.023) analysis. In conclusion, SPOP and FOXA1 mutations may have prognostic value in ERG wt tumors. Interestingly, in absence of SPOP mutations, downregulation of this gene is a feature of many ERG-rearranged prostate tumors.

TMPRSS2-ERG fusions linked to prostate cancer racial health disparities: A focus on Africa.

BackgroundThe androgen‐regulated gene TMPRSS2 to the ETS transcription factor gene ERG fusion is the most common genomic alteration acquired during prostate tumorigenesis and biased toward men of European ancestry. In contrast, African American men present with more advanced disease, yet their tumors are less likely to acquire TMPRSS2‐ERG. Data for Africa is scarce.MethodsRNA was made available for genomic analyses from 181 prostate tissue biopsy cores from Black South African men, 94 with and 87 without pathological evidence for prostate cancer. Reverse transcription polymerase chain reaction was used to screen for the TMPRSS2‐ERG fusion, while transcript junction coordinates and isoform frequencies, including novel gene fusions, were determined using targeted RNA sequencing.ResultsHere we report a frequency of 13% for TMPRSS2‐ERG in tumors from Black South Africans. Present in 12/94 positive versus 1/87 cancer negative prostate tissue cores, this suggests a 92.62% predictivity for a positive cancer diagnosis (P = 0.0031). At a frequency of almost half that reported for African Americans and roughly a quarter of that reported for men of European ancestry, acquisition of TMPRSS2‐ERG appears to be inversely associated with aggressive prostate cancer. Further support was provided by linking the presence of TMPRSS2‐ERG to low‐grade disease in younger patients (P = 0.0466), with higher expressing distal ERG fusion junction coordinates.ConclusionsOnly the second study of its kind for the African continent, we support a link between TMPRSS2‐ERG status and prostate cancer racial health disparity beyond the borders of the United States. We call for urgent evaluation of androgen deprivation therapy within Africa.

SNW1 is a prognostic biomarker in prostate cancer

BackgroundSNW1 is a nuclear receptor co-activator involved in splicing and transcription control, including androgen receptor signaling. Overexpression of SNW1 has been linked to adverse prognosis in different cancer types, but studies on the role of SNW1 in prostate cancer are lacking.MethodsUsing immunohistochemistry, we analyzed SNW1 expression in 10,310 prostate cancers in a tissue microarray (TMA) with attached clinical and molecular data.ResultsThe comparison with normal prostate tissue revealed an up regulation of SNW1 in a subset of cancer samples. SNW1 staining was considered weak in 31.5%, moderate in 37.7% and strong in 14% of cancers. Strong SNW1 expression was markedly more frequent in prostate cancers harboring the TMPRSS2:ERG fusion (24%) than in ERG negative cancers (7%, p < 0.0001). Significant associations with Gleason grade, stage, nodal status and early biochemical recurrence were observed in the ERG negative and positive subset. Multivariable modeling revealed that the prognostic value of SNW1 up regulation was independent from the established preoperative histopathological and clinical parameters.ConclusionThese results demonstrate that SNW1 overexpression is an independent prognostic marker in prostate cancer with potential clinical utility.

OC-0635 Targeting TEMPRSS2:ERG fusion to achieve a tumor-specific radiosensitization in prostate cancer

OC-0635 Targeting TEMPRSS2:ERG fusion to achieve a tumor-specific radiosensitization in prostate cancer

For Physicians Managing Voiding Dysfunction, Improving the Detection Rate of Early Prostate Cancer and Discrimination From Benign Prostatic Hyperplasia, in a Molecular Biomarker Aspects.

Prostate cancer (CaP) is the most common cancer diagnosed among men in the United States and the fifth most common cancer among men in Korea. Unfortunately, the early stages of CaP may have no symptoms. Thus, early detection is very important and physicians managing voiding dysfunction must have awareness about CaP. The traditional tests used for early detection of CaP are the prostate-specific antigen (PSA) blood test and digital rectal examination. However, a high PSA level is not specific for CaP. Benign prostatic hyperplasia, prostatitis, urinary tract infection, and urinary retention can all cause a high PSA level. Thus, no test shows sufficient accuracy to truly be useful for screening men for CaP. A prostate biopsy is the only method that yields a definitive diagnosis of CaP; however, this test is invasive and uncomfortable. Recently, new biomarkers for CaP detection have been proposed to improve the accuracy of the PSA test. In this review, we summarize our knowledge of various new biomarkers, including PSA-associated biomarkers (the prostate health index and 4Kscore), molecular biomarkers (PCA3, TMPRSS2: ERG fusion gene, and various miRNAs), and proteomics-associated biomarkers, and the ways in which they may improve the detection rate of CaP. Accordingly, this review can raise awareness about CaP to physicians managing voiding dysfunction and be a good reference for them.

Characterization of the ERG-regulated Kinome in Prostate Cancer Identifies TNIK as a Potential Therapeutic Target

Approximately 50% of prostate cancers harbor the TMPRSS2:ERG fusion, resulting in elevated expression of the ERG transcription factor. Despite the identification of this subclass of prostate cancers, no personalized therapeutic strategies have achieved clinical implementation. Kinases are attractive therapeutic targets as signaling networks are commonly perturbed in cancers. The impact of elevated ERG expression on kinase signaling networks in prostate cancer has not been investigated. Resolution of this issue may identify novel therapeutic approaches for ERG-positive prostate cancers. In this study, we used quantitative mass spectrometry-based kinomic profiling to identify ERG-mediated changes to cellular signaling networks. We identified 76 kinases that were differentially expressed and/or phosphorylated in DU145 cells engineered to express ERG. In particular, the Traf2 and Nck-interacting kinase (TNIK) was markedly upregulated and phosphorylated on multiple sites upon ERG overexpression. Importantly, TNIK has not previously been implicated in prostate cancer. To validate the clinical relevance of these findings, we characterized expression of TNIK and TNIK phosphorylated at serine 764 (pS764) in a localized prostate cancer patient cohort and showed that nuclear enrichment of TNIK (pS764) was significantly positively correlated with ERG expression. Moreover, TNIK protein levels were dependent upon ERG expression in VCaP cells and primary cells established from a prostate cancer patient-derived xenograft. Furthermore, reduction of TNIK expression and activity by silencing TNIK expression or using the TNIK inhibitor NCB-0846 reduced cell viability, colony formation and anchorage independent growth. Therefore, TNIK represents a novel and actionable therapeutic target for ERG-positive prostate cancers that could be exploited to develop new treatments for these patients.

Ductal and acinar carcinomas of the prostate: A comparative comprehensive genomic profiling study.

271 Background: Prostatic ductal carcinoma (PDC) is an uncommon centrally located prostate with a characteristic tubulopapillary histology. PDC shares some biomarker features with the more common prostatic acinar carcinoma (PAC) including PSA expression. Methods: In this comparative comprehensive genomic profiling (CGP) study, FFPE samples from 61 clinically advanced PDC and 4,132 PAC were profiled for all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Results: The age, frequency of genomic alterations (GA) per tumor and TP53 GA of PDA and PAC were similar (Table). TMPRSS2:ERG fusions and AR GA were more often identified in PAC than PDC whereas PTEN GA were more common in PDC than PAC. Targetable GA were identified at similar frequencies in both groups focused on BRCA2 (PARP inhibitors), BRAF (BRAF/MEK inhibitors) and PIK3CA (MTOR inhibitors). ATM GA (PARP inhibitors) were more common in PAC than PDC. CDK12 GA potentially associated with immunotherapy (IO) benefit were similar in PDA and PAC as were the frequencies of MSI-High status, median TMB and high TMB levels. Conclusions: The pathologic features of PDC and PAC have been classically maintained as representative of 2 different tumor types with potentially contrasting histogenesis. In the current CGP-based study, PDA and PAC did not display significant differences in genomic signatures. CGP may reveal biomarkers that could direct patients to targeted (PARP, MTOR and BRAF/MEK inhibitors) or immunotherapies ( CDK12 GA, MSI-High or high TMB status) in both PDA and PAC. [Table: see text]

Genomic findings in adenocarcinoma of the urinary bladder.

132 Background: Prostatic ductal carcinoma (PDC) is an uncommon centrally located prostate with a characteristic tubulopapillary histology. PDC shares some biomarker features with the more common prostatic acinar carcinoma (PAC) including PSA expression. Methods: In this comparative comprehensive genomic profiling (CGP) study, FFPE samples from 61 clinically advanced PDC and 4,132 PAC were profiled for all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Results: The age, frequency of genomic alterations (GA) per tumor and TP53 GA of PDA and PAC were similar (Table). TMPRSS2:ERG fusions and AR GA were more often identified in PAC than PDC whereas PTEN GA were more common in PDC than PAC. Targetable GA were identified at similar frequencies in both groups focused on BRCA2 (PARP inhibitors), BRAF (BRAF/MEK inhibitors) and PIK3CA (MTOR inhibitors). ATM GA (PARP inhibitors) were more common in PAC than PDC. CDK12 GA potentially associated with immunotherapy (IO) benefit were similar in PDA and PAC as were the frequencies of MSI-High status, median TMB and high TMB levels. Conclusions: The pathologic features of PDC and PAC have been classically maintained as representative of 2 different tumor types with potentially contrasting histogenesis. In the current CGP-based study, PDA and PAC did not display significant differences in genomic signatures. CGP may reveal biomarkers that could direct patients to targeted (PARP, MTOR and BRAF/MEK inhibitors) or immunotherapies ( CDK12 GA, MSI-High or high TMB status) in both PDA and PAC. [Table: see text]

Aberrant expression of the microtubule-associated protein tau is an independent prognostic feature in prostate cancer

BackgroundMicrotubule-associated protein Tau (MAPT) overexpression has been linked to poor prognosis and decreased response to taxane-based therapies in several cancer types, but its relevance in prostate cancer is unknown.MethodsIn this study, MAPT expression was analyzed by immunohistochemistry on a tissue microarray containing 17,747 prostate cancers.ResultsMAPT was absent in normal prostate epithelial cells but detectable in 1004 (8.2%) of 12,313 interpretable cancers. Its expression was associated with advanced tumor stage, high Gleason grade, positive lymph nodes, and early biochemical recurrence (p < 0.0001 each). For example, MAPT was found in 3.6% of 2072 Gleason ≤3 + 3 cancers but in 14.4% of 704 Gleason ≥4 + 4 cancers. High-level MAPT staining was also linked to TMPRSS2:ERG fusions (p < 0.0001). MAPT staining was seen in 15.2 and 16% of cancers with TMPRSS2:ERG fusion detected by immunohistochemistry and fluorescence in-situ hybridization, but in only 3.5 and 3.9% of cancers without ERG staining or ERG rearrangements. Moreover, an association was found between MAPT expression and PTEN deletions, with 19% MAPT positivity in 948 PTEN deleted cancers but only 7% MAPT positivity in 3895 tumors with normal PTEN copy numbers (p < 0.0001). Multivariate analysis revealed that the prognostic value of MAPT was independent from established parameters. Conventional large section analyses showed intratumoral MAPT heterogeneity in all three analyzed cancers.ConclusionsThe results of our study identify MAPT, as a moderate prognostic marker in prostate cancer, whose clinical impact, however, may be limited due to the rarity and heterogeneity of its expression.

Enabling precision medicine by unravelling disease pathophysiology: quantifying signal transduction pathway activity across cell and tissue types

Signal transduction pathways are important in physiology and pathophysiology. Targeted drugs aim at modifying pathogenic pathway activity, e.g., in cancer. Optimal treatment choice requires assays to measure pathway activity in individual patient tissue or cell samples. We developed a method enabling quantitative measurement of functional pathway activity based on Bayesian computational model inference of pathway activity from measurements of mRNA levels of target genes of the pathway-associated transcription factor. Oestrogen receptor, Wnt, and PI3K-FOXO pathway assays have been described previously. Here, we report model development for androgen receptor, Hedgehog, TGFβ, and NFκB pathway assays, biological validation on multiple cell types, and analysis of data from published clinical studies (multiple sclerosis, amyotrophic lateral sclerosis, contact dermatitis, Ewing sarcoma, lymphoma, medulloblastoma, ependymoma, skin and prostate cancer). Multiple pathway analysis of clinical prostate cancer (PCa) studies showed increased AR activity in hyperplasia and primary PCa but variable AR activity in castrate resistant (CR) PCa, loss of TGFβ activity in PCa, increased Wnt activity in TMPRSS2:ERG fusion protein-positive PCa, active PI3K pathway in advanced PCa, and active PI3K and NFκB as potential hormonal resistance pathways. Potential value for future clinical practice includes disease subtyping and prediction and targeted therapy response prediction and monitoring.

Clinical relevance of gene expression in localized and metastatic prostate cancer exemplified by FABP5.

Fatty acid-binding protein 5 (FABP5), a transport protein for lipophilic molecules, has been proposed as protein marker in prostate cancer (PCa). The role of FABP5 gene expression is merely unknown. In two cohorts of PCa patients who underwent radical prostatectomy (n = 40 and n = 57) and one cohort of patients treated with palliative transurethral resection of the prostate (pTUR-P; n = 50) FABP5 mRNA expression was analyzed with qRT-PCR. Expression was correlated with clinical parameters. BPH tissue samples served as control. To independently validate findings on FABP5 expression, three microarray and sequencing datasets were reanalyzed (MSKCC 2010 n = 216; TCGA 2015 n = 333; mCRPC, Nature Medicine 2016 n = 114). FABP5 expression was correlated with ERG-fusion status, TCGA subtypes, cancer driver mutations and the expression of druggable downstream pathway components. FABP5 was overexpressed in PCa compared to BPH in the cohorts analyzed by qRT-PCR (radical prostatectomy p = 0.003, p = 0.010; pTUR-P p = 0.002). FABP5 expression was independent of T stage, Gleason Score, nodal status and PSA level. FABP5 overexpression was associated with the absence of TMPRSS2:ERG fusion (p < 0.001 in TCGA and MSKCC). Correlation with TCGA subtypes revealed FABP5 overexpression to be associated with SPOP and FOXA1 mutations. FABP5 was positively correlated with potential drug targets located downstream of FABP5 in the PPAR-signaling pathway. FABP5 overexpression is frequent in PCa, but seems to be restricted to TMPRESS2:ERG fusion-negative tumors and is associated with SPOP and FOXA1 mutations. FABP5 overexpression appears to be indicative for increased activity in PPAR signaling, which is potentially druggable.

Prostate Cancer Transcriptomic Subtypes.

While the DNA of a tumor is often equated to a fingerprint or its unique genetic identify, a tumor's RNA profile represents a complex dynamic state more akin to a tumors personality or distinct behavior. Of the 11 types of RNA, the translational and clinical focus in prostate cancer has been primarily on mRNA and lncRNA. The most common use of RNA-based biomarkers is to assess a tumor's aggressiveness or treatment sensitivity. However, multiple gene expression signatures have been developed to capture the functional state that results from canonical DNA alterations, including ERG fusions, SPOP mutations, and Rb loss. More commonly, these biomarkers have been used to develop over 30 prognostic gene expression signatures, three of which are now commercially available and being increasingly incorporated into clinical trials. In parallel, the ability to use microarray and RNAseq technologies have allowed high throughput methods of performing whole transcriptomic analyses. This has enabled the discovery and training of numerous predictive biomarker signatures rooted in biologically informed pathways to determine which tumors are more sensitive or resistant to various treatments, including androgen-deprivation therapy, radiotherapy, chemotherapy, and PARP inhibition. This chapter will review the various types of RNA, technologies available to assess gene expression, and describe the available gene expression signatures for prostate cancer.

Loss of PSP94 expression is associated with early PSA recurrence and deteriorates outcome of PTEN deleted prostate cancers.

ObjectiveProstate secretory protein of 94 amino acids (PSP94) is a target gene of the EZH2 transcriptional repressor and is often downregulated in prostate cancer; however, its prognostic value is disputed.MethodsImmunohistochemical analysis of a tissue microarray of 12, 432 prostate cancer specimens was performed to evaluate PSP94 expression. Correlation of PSP94 expression with tumor phenotype, patient prognosis, TMPRSS2:ERG fusion status, EZH2 expression and PTEN deletion was studied. ResultsPSP94 expression was increased in benign prostatic hyperplasia; however, it was downregulated in 48% and negative in 42% of the 9, 881 interpretable prostate cancer specimens. The loss of PSP94 expression was inversely correlated to EZH2 expression (P < 0.0001) and largely unrelated to the ERG status, but strongly correlated with high Gleason grade, advanced tumor stage, and nodal metastasis ( P <0.0001 each). The fraction of PSP94-negative cancer specimens increased from 40% in pT2 to 52% in pT3b-pT4 ( P < 0.0001) and from 40% in Gleason 3+3 = 6 to 46% in Gleason 4+3 = 7 and 60% in Gleason ≥4+4 = 8 ( P < 0.0001). Loss of PSP94 was linked to early prostate-specific antigen recurrence, but with little absolute effect ( P < 0.0001). However, it provided additional prognostic impact in cancer specimens with PTEN deletion. Loss of PSP94 deteriorated prognosis of cancer patients with PTEN deletion by more than 10% (P < 0.0001). The combination of PTEN deletion and PSP94 loss provided independent prognostic information that was observed in several subgroups defined by classical and quantitative Gleason grade. ConclusionsThe results of our study suggest that combined PSP94/PTEN analysis can be potentially used in the clinical prognosis of prostate cancer.

Modeling human prostate cancer progression in vitro.

Detailed mechanisms involved in prostate cancer (CaP) development and progression are not well understood. Current experimental models used to study CaP are not well suited to address this issue. Previously, we have described the hormonal progression of non-tumorigenic human prostate epithelial cells (BPH1) into malignant cells via tissue recombination. Here, we describe a method to derive human cell lines from distinct stages of CaP that parallel cellular, genetic and epigenetic changes found in patients with cancers. This BPH1-derived Cancer Progression (BCaP) model represents different stages of cancer. Using diverse analytical strategies, we show that the BCaP model reproduces molecular characteristics of CaP in human patients. Furthermore, we demonstrate that BCaP cells have altered gene expression of shared pathways with human and transgenic mouse CaP data, as well as, increasing genomic instability with TMPRSS2-ERG fusion in advanced tumor cells. Together, these cell lines represent a unique model of human CaP progression providing a novel tool that will allow the discovery and experimental validation of mechanisms regulating human CaP development and progression. This BPH1-derived Cancer Progression (BCaP) model represents different stages of cancer. The BCaP model reproduces molecular characteristics of prostate cancer. The cells have altered gene expression with TMPRSS2-ERG fusion representing a unique model for prostate cancer progression.

Whole-Genome Sequencing Reveals Elevated Tumor Mutational Burden and Initiating Driver Mutations in African Men with Treatment-Naïve, High-Risk Prostate Cancer.

: African-American men are more likely than any other racial group to die from prostate cancer. The contribution of acquired genomic variation to this racial disparity is largely unknown, as genomic from Africa is lacking. Here, we performed the first tumor-normal paired deep whole-genome sequencing for Africa. A direct study-matched comparison between African- and European-derived, treatment-naïve, high-risk prostate tumors for 15 cases allowed for further comparative analyses of existing data. Excluding a single hypermutated tumor with 55 mutations per megabase, we observed a 1.8-fold increase in small somatic variants in African- versus European-derived tumors (P = 1.02e-04), rising to 4-fold when compared with published tumor-matched data. Furthermore, we observed an increase in oncogenic driver mutations in African tumors (P = 2.92e-03); roughly 30% of impacted genes were novel to prostate cancer, and 79% of recurrent driver mutations appeared early in tumorigenesis. Although complex genomic rearrangements were less frequent in African tumors, we describe a uniquely hyperduplicated tumor affecting 149 transposable elements. Comparable with African Americans, ERG fusions and PIK3CA mutations were absent and PTEN loss less frequent. CCND1 and MYC were frequently gained, with somatic copy-number changes more likely to occur late in tumorigenesis. In addition to traditional prostate cancer gene pathways, genes regulating calcium ion-ATPase signal transduction were disrupted in African tumors. Although preliminary, our results suggest that further validation and investigation into the potential implications for elevated tumor mutational burden and tumor-initiating mutations in clinically unfavorable prostate cancer can improve patient outcomes in Africa. SIGNIFICANCE: The first whole-genome sequencing study for high-risk prostate cancer in African men allows a simultaneous comparison of ethnic differences relative to European populations and of the influences of the environment relative to African-American men. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/78/24/6736/F1.large.jpg.See related commentary by Huang, p. 6726.

Loss of CCAAT-enhancer-binding protein alpha (CEBPA) is linked to poor prognosis in PTEN deleted and TMPRSS2:ERG fusion type prostate cancers.

The transcription factor CCAAT-enhancer-binding protein alpha (CEBPA) is a crucial regulator of cell proliferation and differentiation. Expression levels of CEBPA have been suggested to be prognostic in various tumor types. Here, we analyzed the immunohistochemical expression of CEBPA in a tissue microarray containing more than 17 000 prostate cancer specimens with annotated clinical and molecular data including for example TMPRSS2:ERG fusion and PTEN deletion status. Normal prostate glands showed moderate to strong CEBPA staining, while CEBPA expression was frequently reduced (40%) or lost (30%) in prostate cancers. Absence of detectable CEBPA expression was markedly more frequent in ERG negative (45%) as compared to ERG positive cancers (20%, P < 0.0001). Reduced CEBPA expression was linked to unfavorable phenotype (P < 0.0001) and poor prognosis (P = 0.0008). Subgroup analyses revealed, that the prognostic value of CEBPA loss was entirely driven by tumors carrying both TMPRSS2:ERG fusions and PTEN deletions. In this subgroup, CEBPA loss was tightly linked to advanced tumor stage (P < 0.0001), high Gleason grade (P < 0.0001), positive nodal stage (0.0003), and early biochemical recurrence (P = 0.0007), while these associations were absent or markedly diminished in tumors with normal PTEN copy numbers and/or absence of ERG fusion. CEBPA is down regulated in about one third of prostate cancers, but the clinical impact of CEBPA loss is strictly limited to the subset of about 10% prostate cancers carrying both ERG fusion and deletions of the PTEN tumor suppressor. Our findings challenge the concept that prognostic molecular markers may be generally applicable to all prostate cancers.

Deletion of 3p13 is a late event linked to progression of TMPRSS2:ERG fusion prostate cancer.

IntroductionDeletion of 3p13 is one of the most common alterations in prostate cancer preferentially occurring in tumors with TMPRSS2:ERG fusion. The cause for the striking association between 3p13 loss and ERG fusion is unknown.MethodsHere, we made use of a preexisting heterogeneity prostate cancer tissue microarray including ten tissue spots from ten different tumor areas of 317 cancers to examine the spatial distribution of 3p13 deletions (determined by fluorescence in situ hybridization) in prostate cancer areas with and without ERG overexpression (determined by immunohistochemistry).Results3p13 deletions were found in 61 of 299 (20.4%) and ERG positivity in 174 of 317 (54.9%) interpretable cancers. The likelihood of 3p13 loss was twice as high in ERG-positive cancers (39/152, 25.7%) than in ERG-negative cancers (17/124, 13.7%, P=0.010). At least three tissue spots were interpretable for 3p13 deletion status in 279 cancers: only these were used for heterogeneity assessment. Among these tumors, 58 (20.8%) had a 3p13 deletion and 221 (79.2%) were undeleted. The majority of 3p13-deleted cancers showed marked intratumoral heterogeneity. Areas with and without 3p13 loss were found in 50 (18%) of 279 cancers with three or more interpretable tissue spots, while only eight (3%) tumors had a homogeneous 3p13 loss. Comparison with ERG data revealed that ERG fusion usually precede 3p13 deletions. In total, 26 (66.7%) of 39 cancers with ERG and 3p13 alteration had only focal 3p13 deletions in an otherwise ERG-positive background. In contrast, none of the cancers showed a pattern that would be consistent with 3p13 deletion preceding ERG fusion.ConclusionOur study identifies 3p13 deletion as a highly heterogeneous alteration in prostate cancer preferentially developing at rather late stages of progression in TMPRSS2:ERG fusion-positive tumors.

A Prospective Study of Aspirin Use and Prostate Cancer Risk by TMPRSS2:ERG Status.

Background: In a case-control study, aspirin use was associated with a lower risk of a common prostate cancer molecular subtype, the TMPRSS2:ERG gene fusion. We sought to validate this finding in a prospective cohort.Methods: In the Health Professionals Follow-up Study, 49,395 men reported on aspirin use on biennial questionnaires and were followed for prostate cancer incidence over 23 years. TMPRSS2:ERG status was assessed by IHC for presence of ERG on archival tumor specimens for 912 patients with prostate cancer, of whom 48% were ERG-positive.Results: In multivariable models, we found no association between regular use of aspirin and risk of ERG-positive prostate cancer (HR, 1.02; 95% confidence interval, 0.85-1.23), nor any association with duration or frequency of aspirin use. In restricting to cases with either high Gleason grade or advanced stage disease, there remained no association with aspirin use.Conclusions: Data from this prospective study with repeated assessments of aspirin use do not support the hypothesis that aspirin use is associated with a lower risk of ERG-positive prostate cancer.Impact: Aspirin use is unlikely to lower the risk of this common molecular subtype of prostate cancer. However, there is emerging data supporting the role of other lifestyle and genetic factors underlying the development of the TMPRSS2:ERG fusion. Cancer Epidemiol Biomarkers Prev; 27(10); 1231-3. ©2018 AACR.

Transcriptional Reprogramming and Inhibition of Tumor-propagating Stem-like Cells by EC-8042 in ERG-positive Prostate Cancer

BackgroundThe TMPRSS2-ERG gene fusion is the most frequent genetic rearrangement in prostate cancers and results in broad transcriptional reprogramming and major phenotypic changes. Interaction and cooperation of ERG and SP1 may be instrumental in sustaining the tumorigenic and metastatic phenotype and could represent a potential vulnerability in ERG fusion–positive tumors. ObjectiveTo test the activity of EC-8042, a compound able to block SP1, in cellular and mouse models of ERG-positive prostate cancer. Design, setting, and participantsWe evaluated the activity of EC-8042 in cell cultures and ERG/PTEN transgenic/knockout mice that provide reliable models for testing novel therapeutics in this specific disease context. Using a new protocol to generate tumor spheroids from ERG/PTEN mice, we also examined the effects of EC-8042 on tumor-propagating stem-like cancer cells with high self-renewal and tumorigenic capabilities. Outcome measurements and statistical analysisThe efficacy of EC-8042 was determined by measuring the proliferative capacity and target gene expression in cell cultures, invasive and metastatic capabilities in chick chorioallantoic membrane assays, and tumor development in mice. Significance was determined using statistical test. Results and limitationsEC-8042 blocked transcription of ERG-regulated genes and reverted the invasive and metastatic phenotype of VCaP cells. EC-8042 blocked the expansion of stem-like tumor cells in tumor spheroids from VCaP cells and mouse-derived tumors. In ERG/PTEN mice, systemic treatment with EC-8042 inhibited ERG-regulated gene transcription, tumor progression, and tumor-propagating stem-like tumor cells. ConclusionsOur data support clinical testing of EC-8042 for the treatment of ERG-positive prostate cancer in precision medicine approaches. Patient summaryIn this study, EC-8042, a novel compound with a favorable pharmacological and toxicological profile, exhibited relevant activity in cell cultures and in vivo in a genetically engineered mouse model that closely recapitulates the features of clinically aggressive ERG-positive prostate cancer. Our data indicate that further evaluation of EC-8042 in clinical trials is warranted.