High Serine-arginine Protein Kinase 1 Expression with PTEN Loss Defines Aggressive Phenotype of Prostate Cancer Associated with Lethal Outcome and Decreased Overall Survival.

BACKGROUND: Serine-arginine protein kinase 1 (SRPK1) has been implicated in prostate cancer (PCa) progression. However, its prognostic value and association with ERG and PTEN expression, two of the most common genetic alterations, have not been explored fully. OBJECTIVE: We assessed the prognostic value of SRPK1 in association with ERG and PTEN in a cohort of patients managed nonsurgically by androgen deprivation therapy (ADT) for advanced disease. DESIGN SETTING AND PARTICIPANTS: The study cohort consisted of men diagnosed with PCa by transurethral resection of the prostate (TURP; n = 480). The patients were divided into three main groups: incidental (patients with Gleason score [GS] ≤7 with no prior ADT), advanced (patients with GS ≥8 with no prior ADT), and castrate-resistant PCa (patients with prior ADT). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: A total of 480 TURP samples were assessed by immunohistochemistry for SRPK1, ERG, and PTEN, and results were correlated with Gleason grade group (GG), overall survival (OS), and PCa-specific mortality (PCSM). RESULTS AND LIMITATIONS: High SRPK1 expression was noted in 105/455 (23%) available patient cores. Expression of SRPK1 was associated with Gleason grade grouping (p < 0.0001) with high expression detected in 22/74 (33%) with GG 5. High SRPK1 was not associated with ERG positivity (p = 0.18) but was significantly associated with PTEN intensity (p = 0.001). High SRPK1 was associated with OS (hazard ratio [HR] 1.99; confidence interval [CI]: 1.57-2.54, p < 0.0001) and PCSM (HR 1.64; CI: 1.19-2.26, p < 0.002). Adjusting for Gleason score, patients with high SRPK1 and negative PTEN had the worst clinical outcome for both OS and PCSM compared with other patients (p < 0.0001, HR: 3.02; CI: 1.87-4.88 and HR: 6.40, CI: 3.19-12.85, respectively). CONCLUSIONS: High SRPK1 is associated with worse OS and PCSM. Moreover, patients with high SRPK1 expression and loss of PTEN had the worst clinical outcome for OS and cancer-specific mortality. Combined status of SRPK1 and PTEN may provide added value in stratifying patients into various prognostic groups. PATIENT SUMMARY: The expression of serine-arginine protein kinase 1 (SRPK1) combined with PTEN has a significant prognostic role in prostate cancer patients. Patients with high SRPK1 expression and negative PTEN had the worst clinical outcome for overall survival and cancer-specific mortality.

Expression of ISL1 and its partners in prostate cancer progression and neuroendocrine differentiation.

INTRODUCTION AND OBJECTIVES: ISL1 serves as a biomarker of metastasis and neuroendocrine neoplasia in multiple tumors. However, the expression and relation of ISL1 to other biomarkers in prostate cancer have not been fully elucidated. Here, we characterize the expression of ISL1 and its partners in PCa and document its association to disease progression and post castration resistance neuroendocrine differentiation. METHODS: The expression of ISL1 was interrogated in > 6000 primary samples from the Decipher GRID registry and 250 mCRPC samples to assess its prognostic value and relation to neuroendocrine differentiation. RESULTS: ISL1 was highly correlated to MEIS genes and other genes related to cell motility. ISL1 down-regulation in PCa was associated with cancer progression, aggressive primary tumors, and metastatic outcome. We found that ISL1 is highly correlated to MEIS genes across multiple primary PCa and mCRPC cohorts. The expression of ISL1 and MEIS genes were significantly and inversely related to metastasis-free survival and lethal disease, and were downregulated in CRPC and hormone naïve metastatic tumors but showed upregulation in neuroendocrine tumors. Co-immunoprecipitation showed MEIS2 and ISL1 interacting with each supporting their role in modulating transcriptional regulation and nominating this complex for potential targeted therapy. CONCLUSIONS: ISL1 complex with MEIS2 serves a critical role in prostate tumor progression and its upregulation in mCRPC/NE provides a rationale for assessing the role of ISL1 and its associated protein in treatment resistance.

Molecular characterization of prostate cancer in Middle Eastern population highlights differences with Western populations with prognostic implication.

BACKGROUND: To investigate the incidence and prognostication of ERG, PTEN and SPINK1 protein expressions in prostate cancer cohort of Middle Eastern descent in comparison to published data from Western population. METHODS: Immunohistochemistry for ERG, PTEN and SPINK1 was performed in a cohort of localized PCA (n = 340). The data were correlated to pathological and clinical outcomes and compared to Western populations. RESULTS: ERG expression and PTEN loss were noted in 123/288 (42.7%) and 91/297 (30.6%) of patients, respectively. SPINK1 expression was assessed in a subset of cases, noted in 6/150 (4%) of patients. Only ERG expression was associated with grade groups, being more common in the lower grade groups (1-3 vs 4-5; p = 0.04). In contrast to the Western population, PTEN loss foci were more likely to be ERG negative, observed in 81% of tumor foci and patients with PTEN neg/ERG pos were more likely to exhibit biochemical recurrence (OR 2.831; 95% CI 1.10-726, p = 0.03). This association remained significant in multivariate analysis (OR 2.68; 95% CI 0.98-7.33, p = 0.05), after adjusting for GG, path stage and surgical margin. CONCLUSION: This study documents significant differences in key molecular events in PCA in Middle Eastern population compared to Western populations that could explain differences in PCA incidence, progression and prognostication. ERG, PTEN and SPINK1 genomic alteration occur less frequently and the enrichment of ERG for PTEN loss is not observed. Additionally, patients with combined PTEN loss/ERG positive are at highest risk for BCR vs North American Caucasian population where PTEN loss alone seems to be associated with the worst clinical outcome. The data presented here further support differences in clonal evolution between Middle Eastern and Western population in relation to PCA and add further insight to understanding PCA molecular pathways.

Combined loss of TFF3 and PTEN is associated with lethal outcome and overall survival in men with prostate cancer.

BACKGROUND: Trefoil Factor 3 (TFF3) has been implicated in Prostate Cancer (PCa) progression. However, its prognostic value and association with other biomarkers have not been fully explored. We assessed the combined value of TFF3 and PTEN in two cohorts: one is managed surgically for localized PCa and the second is managed non-surgically by androgen deprivation therapy for advanced disease. DESIGN: 228 radical prostatectomies (RP) and 318 transurethral resection of prostate (TURP) samples were assessed by immunohistochemistry (IHC) for TFF3 and by IHC and fluorescent in situ hybridization (FISH) for PTEN. Results of biomarkers expression were correlated with various pathological and clinical outcome parameters including biochemical recurrence (BCR) in the RP cohort and cancer-specific mortality (PCSM) and overall survival (OS) in the TURP cohort. RESULTS: TFF3 expression was detected in 131/226 (57.9%) RP samples and 148/318 (46.5%) of TURP cases. In general, TFF3 positivity was less frequently observed with advanced Gleason Groups. TFF3 expression was also assessed in relation to PTEN expression. Only 15-16% of TFF3-expressed cases were present in association with complete loss of PTEN expression in the TURP and localized cohorts, respectively. Loss of TFF3 expression was not related to BCR after RP, but was prognostic in the non-surgical cohort and associated with decrease OS and PCSM (HR 2.31, CI: 1.67-3.18, p < 0.0001) and (HR 3.99, CI: 2.43-6.56; p < 0.0001), respectively. Adjusting for Gleason score, combined loss of TFF3/PTEN was most associated with OS (HR 2.33, CI: 1.49-3.62; p < 0.0001) and PCSM (HR = 3.44, CI: 1.75-6.78, p < 0.0001). CONCLUSION: The study documents for the first time significant association for combined status of TFF3 expression and PTEN loss in OS and PCSM in patients not managed by surgical intervention. Prospective assessment of PTEN and TFF3 may provide further insight into molecularly subtyping PCa and aid in stratifying patients at risk for lethal disease.

Validation of the Decipher Test for predicting adverse pathology in candidates for prostate cancer active surveillance.

ABSTACT: BACKGROUND: Many men diagnosed with prostate cancer are active surveillance (AS) candidates. However, AS may be associated with increased risk of disease progression and metastasis due to delayed therapy. Genomic classifiers, e.g., Decipher, may allow better risk-stratify newly diagnosed prostate cancers for AS. METHODS: Decipher was initially assessed in a prospective cohort of prostatectomies to explore the correlation with clinically meaningful biologic characteristics and then assessed in diagnostic biopsies from a retrospective multicenter cohort of 266 men with National Comprehensive Cancer Network (NCCN) very low/low and favorable-intermediate risk prostate cancer. Decipher and Cancer of the Prostate Risk Assessment (CAPRA) were compared as predictors of adverse pathology (AP) for which there is universal agreement that patients with long life-expectancy are not suitable candidates for AS (primary pattern 4 or 5, advanced local stage [pT3b or greater] or lymph node involvement). RESULTS: Decipher from prostatectomies was significantly associated with adverse pathologic features (p-values < 0.001). Decipher from the 266 diagnostic biopsies (64.7% NCCN-very-low/low and 35.3% favorable-intermediate) was an independent predictor of AP (odds ratio 1.29 per 10% increase, 95% confidence interval [CI] 1.03-1.61, p-value 0.025) when adjusting for CAPRA. CAPRA area under curve (AUC) was 0.57, (95% CI 0.47-0.68). Adding Decipher to CAPRA increased the AUC to 0.65 (95% CI 0.58-0.70). NPV, which determines the degree of confidence in the absence of AP for patients, was 91% (95% CI 87-94%) and 96% (95% CI 90-99%) for Decipher thresholds of 0.45 and 0.2, respectively. Using a threshold of 0.2, Decipher was a significant predictor of AP when adjusting for CAPRA (p-value 0.016). CONCLUSION: Decipher can be applied to prostate biopsies from NCCN-very-low/low and favorable-intermediate risk patients to predict absence of adverse pathologic features. These patients are predicted to be good candidates for active surveillance.

Validation of a 10-gene molecular signature for predicting biochemical recurrence and clinical metastasis in localized prostate cancer.

PURPOSE: To validate a previously characterized 10-gene signature in prostate cancer with implication to distinguish aggressive and indolent disease within low and intermediate patients' risk groups. METHODS: A case-control study design used to select 545 patients from the Mayo clinic tumor registry who underwent radical prostatectomy. A training set from this cohort (n = 359) was used to build a 10-gene model, based on high-dimensional discriminant analysis (HDDA10) to predict several endpoints of clinical patients' outcome. An independent set (n = 219) from the same institution was used as validation set. RESULTS: HDDA10 showed significant performance for predicting metastasis (Mets) (AUC 0.68, p = 6.4E - 6) and biochemical recurrence (BCR) (AUC = 0.65, p = 0.003) in the validation set outperforming Gleason grade grouping (GG) for BCR (AUC 0.57, p = 0.03) and with comparable performance for Mets endpoint (GG AUC 0.66, p = 8.1E - 5). HDDA10 prognostic significance was superior to any clinical-pathological parameter within GG2 + 3 (GS7) patients achieving an AUC of 0.74 (p = 0.0037) for BCR compared to Gleason pattern 4 (AUC 0.64) (p = 0.015) and AUC for Mets of 0.68 versus AUC of 0.65 for Gleason pattern 4 (p = 0.01). HDDA10 remained significant for both BCR and Mets in multivariate analysis, suggesting that it can be used to increase accuracy in stratifying patients eligible for active surveillance. CONCLUSION: HDDA10 is of added value to GG and other clinical-pathological parameters in predicting BCR and Mets endpoint, especially in the low to intermediate patients' risk groups. HDDA10 prognostic value should be further validated prospectively in stratifying patients specifically in low to intermediate GS (GG1-2), such as active surveillance programs.

Eosinophilic Solid and Cystic Renal Cell Carcinoma (ESC RCC): Further Morphologic and Molecular Characterization of ESC RCC as a Distinct Entity.

Eosinophilic solid and cystic renal cell carcinoma (ESC RCC) has been recently described as a unique and indolent renal neoplasm, found in female patients with and without tuberous sclerosis complex. Although ESC RCC has a distinct morphology and frequent CK20 reactivity, its molecular karyotype has been previously studied only in few cases. We identified 19 ESC RCC from multiple institutions; all patients were female individuals without clinical features of tuberous sclerosis complex. Molecular karyotyping was performed in 13 cases (12 with informative result). The median age was 55 years (range: 32 to 79 y). The tumors were yellow-gray with a median size of 31 mm (range: 12 to 135 mm) and showed solid and cystic gross appearance. All tumors demonstrated typical microscopic features with solid areas admixed with variably sized macrocysts and microcysts. The cells showed eosinophilic cytoplasm with granular cytoplasmic stippling and round-to-oval nuclei. CK20 was positive in 14/19 (74%) cases. Stage pT1 was found in 17/19 (89%) patients (pT1a in 12, pT1b in 5); 1 patient each had pT2a and pT3a. A total of 15/16 patients with available follow-up were alive and without evidence of disease progression, after 1 to 169 months (median: 44 mo; mean: 49.6 mo); 3 died of other causes. The most common copy number gains were 16p13.3-16q23.1 (33% to 67%), 7p21.2-7q36.2 (42% to 50%), 13q14.2 (33%), and 19p12 (33%). The most common copy number losses included Xp11.21 (42%) and 22q11.23 (33%). Loss of heterozygosity was most frequently found at 16p11.2-11.1 (75%), Xq11.1-13.1 (75%), Xq13.1-21.1 (33%), 11p11.2-11.11 (33%), 9q21.1-22.2 (33%), and 9q33.1 (33%). ESC RCC demonstrates common molecular karyotype alterations, which further support its distinct nature.

Ankyrin G expression is associated with androgen receptor stability, invasiveness, and lethal outcome in prostate cancer patients.

Ankyrin G (ANK3) is a member of the Ankyrin family, which functions to provide cellular stability by anchoring the cytoskeleton to the plasma membrane. Deregulation of ANK3 expression has been observed in multiple human cancers but its mechanism remains unknown. ANK3 expression in relation to disease progression and patients' outcome was investigated in two cohorts of prostate cancer (PCA). Mechanistic studies were carried out in vitro and in vivo using several PCA cell lines and the avian embryo model. Silencing ANK3 resulted in significant reduction of cell proliferation through an AR-independent mechanism. Decreased ANK3 expression delayed S phase to G2/M cell cycle transition and reduced the expression of cyclins A and B. However, cells with knocked-down ANK3 exhibited significant increase in cell invasion through an AR-dependent mechanism. Furthermore, we found that ANK3 is a regulator of AR protein stability. ANK3 knockdown also promoted cancer cell invasion and extravasations in vivo using the avian embryo model (p < 0.01). In human samples, ANK3 expression was dramatically upregulated in high grade intraepithelial neoplasia (HGPIN) and localized PCA (p < 0.0001). However, it was downregulated castration resistant stage (p < 0.0001) and showed inverse relation to Gleason score (p < 0.0001). In addition, increased expression of ANK3 in cancer tissues was correlated with better cancer-specific survival of PCA patients (p = 0.012). KEY MESSAGE: Silencing ANK3 results in significant reduction of cell proliferation through an AR-independent mechanism. ANK3 knockdown results in significant increase in cell invasion through an AR-dependent mechanism. ANK3 is a regulator of AR protein stability. ANK3 knockdown also promotes cancer cell invasion and extravasation in vivo using the avian embryo model.

microRNA 338-3p exhibits tumor suppressor role and its down-regulation is associated with adverse clinical outcome in prostate cancer patients.

MicroRNAs (miRNAs) are small non-coding RNAs that function in transcriptional and post-transcriptional regulation of gene expression. Several miRNAs have been implicated in regulating prostate cancer (PCa) progression. Deregulations of miRNA regulatory networks have been reported in ERG positive PCa, which accounts for ~50 % of PCa and have been suggested to affect tumor aggressiveness. The function of miR338-3p, its prognostic significance, and its association with ERG positive PCa has not been fully investigated. Using microarray expression profiling, we identified miRNA338-3p as among the top deregulated miRNAs associated with ERG status in PCa. We investigated miR338-3p function using in vitro and in vivo experimental models and its expression was assessed and validated in clinical samples and a public cohort of localized and metastatic prostate cancer. miR338-3p was significantly down-regulated with disease progression from benign prostate tissue to primary and metastatic lesions. In localized disease, patients with lower miR338-3p expression levels showed increased association to biochemical recurrence and several adverse pathological parameters compared to patients with higher miRNA338-3p tissue expression levels. Using in vitro PCa cell models, overexpression of miR338-3p resulted in a decrease in cell invasion and expression of chemokine signalling genes CXCL12, CXCR4, and CXCR7. In vivo, orthotropic implantation of PC3 cells stably expressing miR338-3p was associated with a significant decrease in tumor weights compared to control cells. miR338-3p has anti-proliferative and anti-invasive properties. It affects CXCR4 axis, and its down-regulation is associated with adverse clinical outcomes in PCa patients.

ING3 is associated with increased cell invasion and lethal outcome in ERG-negative prostate cancer patients.

The inhibitor of growth family member 3 (ING3) is a member of the ING tumor suppressor family. Although its expression has been reported in various types of cancers, the role of ING3 and its prognostic value in prostate cancer (PCa) has not been investigated. ING3 expression and prognostic value was assessed in a cohort of PCa patients (n = 312) treated with transurethral resection of prostate using immumoflourescent automated quantitative analysis (AQUA) system. In vitro studies were carried out in conjunction to investigate its expression in various PCa cell lines. ING3 knockdown was also carried out in DU145 cell lines to assess for any changes in invasion and migration. ING3 expression was highest in benign prostate tissues (mean 3.2 ± 0.54) compared to PCa (mean 2.5 ± 0.26) (p = 0.437), advanced prostate cancer (AdvPCa) (mean 1.5 ± 0.32) (p = 0.004), and castration-resistant prostate cancer (CRPC) (mean 2.28 ± 0.32) (p = 0.285). ING3 expression was inversely correlated to Gleason score (p = 0.039) and ETS-related gene (ERG) expression (p = 0.019). Higher ING3 expression was marginally associated with lethal disease (p = 0.052), and this was more pronounced in patients with ERG-negative status (p = 0.018). Inhibition of ING3 in DU145 PCa cells using small interfering RNA (siRNA) was associated with decreased cell invasion (p = 0.0016) and cell migration compared to control cells. ING3 is significantly associated with PCa disease progression and cancer-specific mortality. To our knowledge, this is the first report suggesting an oncogenic function of ING3, previously well known as a tumor suppressor protein. Further studies should investigate potential-related pathways in association to ING3.

ERG expression in prostate cancer: biological relevance and clinical implication.

INTRODUCTION: Screening for increased levels of prostate-specific antigen (PSA) has allowed early detection of a large majority of prostate cancer (PCa) cases. However, the relative lack of specificity of PSA has resulted in significant over-diagnosis and unnecessary treatment for indolent tumors. The fusion of the transmembrane protease serine 2 with E26 transformation-specific family genes, particularly ERG, is the most widespread genetic alteration in prostate cancer, and data suggest that it is more specific for neoplastic prostate disease and may be of added prognostic value and point toward molecular subtype of PCa. METHODS: In this review, retrospective studies and clinical trials were analyzed to highlight the recent advances in our understanding of the cellular consequence of ERG rearrangement, describe its interactions with other genetic and molecular pathways, and discuss its potential diagnostic and prognostic value. CONCLUSION: ERG over-expression has an emerging role in the diagnosis of PCa pathology, although there is still debate about its prognostic value. Elucidation of the mechanisms of ERG gene rearrangements and expression promises novel therapeutic and diagnostic avenues for prostate cancer.