Alignment of molecular subtypes across multiple bladder cancer subtyping classifiers

BACKGROUND

Treatment of patients with muscle-invasive bladder cancer (MIBC) includes cisplatin-based neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC). Molecular subtypes have been associated with patient outcomes after NAC and RC, but the reported results have been highly inconsistent.

OBJECTIVE

To evaluate the association of molecular subtypes from different classifiers with overall survival (OS) among patients with MIBC who underwent RC.

MATERIALS AND METHODS

We analyzed gene expression data generated from transurethral resection of MIBC from a previously assembled and published meta-cohort, NACmeta (N = 601, 247 treated with NAC+RC and 354 RC without NAC), where extended follow-up was available. Molecular subtypes were assigned using the Genomic Subtyping Classifier (GSC), the Consensus Classifier, The Cancer Genome Atlas (TCGA) Classifier, and the Lund Classifier. For survival analysis, inverse probability weighting was used to balance the clinical NAC and non-NAC patient groups.

RESULTS

A high consistency in gene expression patterns and nomenclature was observed between luminal-like subtypes, defined as GSC-Luminal, Consensus-Luminal Papillary (LumP), TCGA Luminal-Papillary (LumP) and Lund-UroA, but not for basal-like subtypes such GSC-Basal, Consensus Basal/Squamous, TCGA-Basal/Squamous and Lund-Basal/Squamous. Patients with luminal-like subtypes demonstrated no difference in 3-year OS when treated with or without NAC (P = 0.7 for GSC, P = 0.94 for Consensus, P = 0.87 for TCGA and P = 0.66 for Lund-UroA, respectively).

CONCLUSION

Luminal-like molecular subtypes identify a subgroup of MIBC patients who do not appear to benefit from current NAC regimens, even for locally advanced disease. In addition, we were able to illustrate differences in subtyping nomenclature that are not reflected in the underlying biological definition of the subtypes.

PATIENT SUMMARY

Muscle-invasive bladder cancer exhibits molecular diversity, and various classifications identify different groups who do not benefit from chemotherapy. On the other hand, there is a high inconsistency in the way cancer groupings are named.

Exploring The Prognostic Significance of SET-Domain Containing 2 (SETD2) Expression in Advanced and Castrate-Resistant Prostate Cancer

SET-domain containing 2 (SETD2) is a histone methyltransferase and an epigenetic modifier with oncogenic functionality. In the current study, we investigated the potential prognostic role of SETD2 in prostate cancer. A cohort of 202 patients' samples was assembled on tissue microarrays (TMAs) containing incidental, advanced, and castrate-resistant CRPCa cases. Our data showed significant elevated SETD2 expression in advanced and castrate-resistant disease (CRPCa) compared to incidental cases (2.53 ± 0.58 and 2.21 ± 0.63 vs. 1.9 ± 0.68; p < 0.001, respectively). Interestingly, the mean intensity of SETD2 expression in deceased vs. alive patients was also significantly different (2.31 ± 0.66 vs. 2 ± 0.68; p = 0.003, respectively). Overall, high SETD2 expression was found to be considered high risk and was significantly associated with poor prognosis and worse overall survival (OS) (HR 1.80; 95% CI: 1.28-2.53, p = 0.001) and lower cause specific survival (CSS) (HR 3.14; 95% CI: 1.94-5.08, p < 0.0001). Moreover, combining high-intensity SETD2 with PTEN loss resulted in lower OS (HR 2.12; 95% CI: 1.22-3.69, p = 0.008) and unfavorable CSS (HR 3.74; 95% CI: 1.67-8.34, p = 0.001). Additionally, high SETD2 intensity with ERG positive expression showed worse prognosis for both OS (HR 1.99, 95% CI 0.87-4.59; p = 0.015) and CSS (HR 2.14, 95% CI 0.98-4.68, p = 0.058). We also investigated the protein expression database TCPA, and our results showed that high SETD2 expression is associated with a poor prognosis. Finally, we performed TCGA PRAD gene set enrichment analysis (GSEA) data for SETD2 overexpression, and our data revealed a potential association with pathways involved in tumor progression such as the AMPK signaling pathway, the cAMP signaling pathway, and the PI3K-Akt signaling pathway, which are potentially associated with tumor progression, chemoresistance, and a poor prognosis.

Genomic Biomarker Discovery in Disease Progression and Therapy Response in Bladder Cancer Utilizing Machine Learning

Cancer in all its forms of expression is a major cause of death. To identify the genomic reason behind cancer, discovery of biomarkers is needed. In this paper, genomic data of bladder cancer are examined for the purpose of biomarker discovery. Genomic biomarkers are indicators stemming from the study of the genome, either at a very low level based on the genome sequence itself, or more abstractly such as measuring the level of gene expression for different disease groups. The latter method is pivotal for this work, since the available datasets consist of RNA sequencing data, transformed to gene expression levels, as well as data on a multitude of clinical indicators. Based on this, various methods are utilized such as statistical modeling via logistic regression and regularization techniques (elastic-net), clustering, survival analysis through Kaplan-Meier curves, and heatmaps for the experiments leading to biomarker discovery. The experiments have led to the discovery of two gene signatures capable of predicting therapy response and disease progression with considerable accuracy for bladder cancer patients which correlates well with clinical indicators such as Therapy Response and T-Stage at surgery with Disease Progression in a time-to-event manner.

Disparities in prostate cancer screening, diagnoses, management, and outcomes between Indigenous and non-Indigenous men in a universal health care system

BACKGROUND

Indigenous Peoples have higher morbidity rates and lower life expectancies than non-Indigenous Canadians. Identification of disparities between Indigenous and non-Indigenous men regarding prostate cancer (PCa) screening, diagnoses, management, and outcomes was sought.

METHODS

An observational cohort of men diagnosed with PCa between June 2014 and October 2022 was studied. Men were prospectively enrolled in the province-wide Alberta Prostate Cancer Research Initiative. The primary outcomes were tumor characteristics (stage, grade, and prostate-specific antigen [PSA]) at diagnosis. Secondary outcomes were PSA testing rates, time from diagnosis to treatment, treatment modality, and metastasis-free, cancer-specific, and overall survivals.

RESULTS

Examination of 1,444,974 men for whom aggregate PSA testing data were available was performed. Men in Indigenous communities were less likely to have PSA testing performed than men outside of Indigenous communities (32 vs. 46 PSA tests per 100 men [aged 50-70 years] within 1 year; p < .001). Among 6049 men diagnosed with PCa, Indigenous men had higher risk disease characteristics: a higher proportion of Indigenous men had PSA ≥ 10 ng/mL (48% vs. 30%; p < .01), TNM stage ≥ T2 (65% vs. 47%; p < .01), and Gleason grade group ≥ 2 (79% vs. 64%; p < .01) compared to non-Indigenous men. With a median follow-up of 40 months (interquartile range, 25-65 months), Indigenous men were at higher risk of developing PCa metastases (hazard ratio, 2.3; 95% CI, 1.2-4.2; p < .01) than non-Indigenous men.

CONCLUSIONS

Despite receiving care in a universal health care system, Indigenous men were less likely to receive PSA testing and more likely to be diagnosed with aggressive tumors and develop PCa metastases than non-Indigenous men.

Cleavage and Polyadenylation-Specific Factor 4 (CPSF4) Expression Is Associated with Enhanced Prostate Cancer Cell Migration and Cell Cycle Dysregulation, In Vitro

Potential oncogene cleavage and polyadenylation specific factor 4 (CPSF4) has been linked to several cancer types. However, little research has been conducted on its function in prostate cancer (PCa). In benign, incidental, advanced, and castrate resistant PCa (CRPCa) patient samples, protein expression of CPSF4 was examined on tissue microarray (TMAs) of 353 PCa patients using immunohistochemistry. Using the 'The Cancer Genome Atlas' Prostate Adenocarcinoma (TCGA PRAD) database, significant correlations were found between high CPSF4 expression and high-risk genomic abnormalities such as ERG-fusion, ETV1-fusion, and SPOP mutations. Gene Set Enrichment Analysis (GSEA) of CPSF4 revealed evidence for the increase in biological processes such as cellular proliferation and metastasis. We further examined the function of CPSF4 in vitro and confirmed CPSF4 clinical outcomes and its underlying mechanism. Our findings showed a substantial correlation between Gleason groups and CPSF4 protein expression. In vitro, CPSF4 knockdown reduced cell invasion and migration while also causing G1 and G2 arrest in PC3 cell lines. Our findings demonstrate that CPSF4 may be used as a possible biomarker in PCa and support its oncogenic function in cellular proliferation and metastasis.

Editorial: The Application of Proteogenomics to Urine Analysis for the Identification of Novel Biomarkers of Prostate Cancer: An Exploratory Study

In this editorial context, we aim to leverage the potential of proteogenomics, which integrates genomic and proteomic data, to discover novel biomarkers that can aid in the diagnosis and management of prostate cancer. We highlight the importance of proteogenomics for understanding the functional consequences of somatic mutations in cancer and demonstrating how proteogenomic analysis can provide insights into the effects of genetic alterations on the proteomic landscape and identify potential therapeutic targets. This article also emphasizes the potential of urine analysis for the detection of prostate cancer. Overall, our editorial paper provides general insights on the application of proteogenomics to urine analysis for the identification of novel biomarkers of prostate cancer.

Large, Nested Variant of Urothelial Carcinoma Is Enriched with Activating Mutations in Fibroblast Growth Factor Receptor-3 among Other Targetable Mutations

The large, nested variant of urothelial carcinoma (LNVUC) is characterized by bland histomorphology mimicking that of benign von Brunn nests. In the current study, we aimed to investigate the Fibroblast Growth Factor Receptor-3 (FGFR-3) activation and missense mutation in 38 cases, including 6 cases diagnosed with LNVUC and 32 with metastatic invasive urothelial carcinoma (UC). Initially, six formalin-fixed paraffin-embedded (FFPE) tissue samples of the LNVUC were subjected to whole-exome sequencing (WES), and then we performed targeted sequencing on 32 cases of metastatic invasive UC of various morphological subtypes, which were interrogated for the FGFR3. Our results revealed 3/6 (50%) LNVUC cases evaluated by WES in our study showed an activating mutation in FGFR-3, 33% showed an activating mutation in PIK3CA, and 17% showed activating mutation in GNAS or MRE11. Additionally, 33% of cases showed a truncating mutation in CDKN1B. All LNVUC in our study that harbored the FGFR-3 mutation showed additional activating or truncating mutations in other genes. Overall, 6/32 (18.75%) cases of random metastatic invasive UC showed missense mutations of the FGFR-3 gene. The LNVUC variant showed the higher incidence of FGFR-3 mutations compared to other types of mutations. Additionally, all LNVUC cases show additional activating or truncating mutations in other genes, thus being amenable to novel targeted therapy.

Serrate RNA Effector Molecule (SRRT) Is Associated with Prostate Cancer Progression and Is a Predictor of Poor Prognosis in Lethal Prostate Cancer

Arsenite-resistance protein 2, also known as serrate RNA effector molecule (ARS2/SRRT), is known to be involved in cellular proliferation and tumorigenicity. However, its role in prostate cancer (PCa) has not yet been established. We investigated the potential role of SRRT in 496 prostate samples including benign, incidental, advanced, and castrate-resistant patients treated by androgen deprivation therapy (ADT). We also explored the association of SRRT with common genetic aberrations in lethal PCa using immunohistochemistry (IHC) and performed a detailed analysis of SRRT expression using The Cancer Genome Atlas (TCGA PRAD) by utilizing RNA-seq, clinical information (pathological T category and pathological Gleason score). Our findings indicated that high SRRT expression was significantly associated with poor overall survival (OS) and cause-specific survival (CSS). SRRT expression was also significantly associated with common genomic aberrations in lethal PCa such as PTEN loss, ERG gain, mutant TP53, or ATM. Furthermore, TCGA PRAD data revealed that high SRRT mRNA expression was significantly associated with higher Gleason scores, PSA levels, and T pathological categories. Gene set enrichment analysis (GSEA) of RNAseq data from the TCGA PRAD cohort indicated that SRRT may play a potential role in regulating the expression of genes involved in prostate cancer aggressiveness. Conclusion: The current data identify the SRRT's potential role as a prognostic for lethal PCa, and further research is required to investigate its potential as a therapeutic target.

Downregulation of BUD31 Promotes Prostate Cancer Cell Proliferation and Migration via Activation of p-AKT and Vimentin In Vitro

Among men, prostate cancer (PCa) is the second most frequently diagnosed cancer subtype and has demonstrated a high degree of prevalence globally. BUD31, also known as Functional Spliceosome-Associated Protein 17, is a protein that works at the level of the spliceosome; it is functionally implicated in pre-mRNA splicing as well as processing, while also acting as a transcriptional regulator of androgen receptor (AR) target genes. Clinically, the expression of BUD31 and its functions in the development and progression of PCa is yet to be elucidated. The BUD31 expression was assessed using IHC in a tissue microarray (TMA) constructed from a cohort of 284 patient samples. In addition, we analyzed the prostate adenocarcinoma (TCGAPRAD-) database. Finally, we used PCa cell lines to knockdown BUD31 to study the underlying mechanisms in vitro.Assesment of BUD31 protein expression revealed lower expression in incidental and advanced PCa, and significantly lower expression was observed in patients diagnosed with castrate-resistant prostate cancer. Additionally, bioinformatic analysis and GSEA revealed that BUD31 increased processes related to cancer cell migration and proliferation. In vitro results made evident that BUD31 knockdown in PC3 cells led to an increase in the G2 cell population, indicating a more active and proliferative state. Additionally, an investigation of metastatic processes revealed that knockdown of BUD31 significantly enhanced the ability of PC3 cells to migrate and invade. Our in vitro results showed BUD31 knockdown promotes cell proliferation and migration of prostate cancer cells via activation of p-AKT and vimentin. These results support the clinical data, where low expression of BUD31 was correlated to more advanced stages of PCa.

Prognostic biomarkers and clinical outcomes in neuroendocrine prostate cancer (NEPC)

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Background: NEPC includes both pure small cell carcinoma and mixed tumors with varying degrees of adenocarcinoma and neuroendocrine histology. It arises de novo or is treatment associated (TA) post androgen deprivation therapy. Clinical outcome data and prognostic biomarkers are limited and were thus explored. Methods: Patients with high grade prostate cancer and morphologic and/or immunohistochemical (IHC) NEPC features were included in this retrospective multicentre study. Clinical stage, Gleason score, and serum biomarkers were recorded. Kaplan-Meier method and log-rank test calculated and compared overall survival (OS) from time of NEPC diagnosis.Cox proportional hazards regression assessed prognostic impact of serum biomarkers at diagnosis and de novo vs TA status, adjusting for clinical stage and castration resistance. Results: 135 NEPC cases were identified. 124 (92%) were mixed tumors. 56 (41%) arose de novo. 79 (59%) were TA. 77% of those with a Gleason score (N=85/110) were grade group 5. Median PSA pre-NEPC biopsy was 11.6 ng/mL. At NEPC diagnosis, 19 (14%) had localized disease (median OS 123.0 mo); 33 (24%) non-metastatic castrate-sensitive disease (median OS 42.3 mo); 6 (4%) non-metastatic castrate-resistant disease (median OS 14.3 mo); 35 (26%) metastatic castrate-sensitive disease (median OS 17.6 mo); and 42 (31%) metastatic castrate-resistant disease (median OS 9.6 mo). Median OS for those with visceral metastases was 8.6 mo (95% CI 6.0 – 14.6), compared to patients with non-visceral metastases (11.1 mo; 95% CI 13.7 – 21.5) and no metastases (42.3 mo; 95% CI 47 – 89). Anemia (adjusted HR 1.66; 95% CI 1.05 - 2.16, p = 0.031) and NLR >3 (adjusted HR 1.51; 95% CI 1.01 - 2.52, p = 0.045) were associated with increased risk of death. De novo disease, elevated LDH, serum PSA, and Gleason score were not prognostic. Conclusions: This study identifies NEPC clinical outcomes by stage, with survival poorer than expected in pure prostate adenocarcinoma. Anemia and elevated NLR >3 are prognostic biomarkers that may help risk stratify and guide treatment intensification, including platinum-based chemotherapy. Further biomarker characterization of NEPC through IHC-staining pattern and genomic analysis is currently underway by this group.

The Association between Cyclin Dependent Kinase 2 Associated Protein 1 (CDK2AP1) and Molecular Subtypes of Lethal Prostate Cancer

Prostate cancer (PCa) is one of the most commonly diagnosed types of malignancy and is the second leading cause of cancer-related death in men in developed countries. Cyclin dependent kinase 2 associate protein 1(CDK2AP1) is an epigenetic and cell cycle regulator gene which has been downregulated in several malignancies, but its involvement in PCa has not yet been investigated in a clinical setting. We assessed the prognostic value of CDK2AP1 expression in a cohort of men diagnosed with PCa (n = 275) treated non-surgically by transurethral resection of the prostate (TURP) and studied the relationship between CDK2AP1 expression to various PCa molecular subtypes (ERG, PTEN, p53 and AR) and evaluated the association with clinical outcome. Further, we used bioinformatic tools to analyze the available TCGA PRAD transcriptomic data to explore the underlying mechanism. Our data confirmed increased expression of CDK2AP1 with higher Gleason Grade Group (GG) and metastatic PCa (p <0.0001). High CDK2AP1 expression was associated with worse overall survival (OS) (HR: 1.62, CI: 1.19−2.21, p = 0.002) and cause-specific survival (CSS) (HR: 2.012, CI 1.29−3.13, p = 0.002) using univariate analysis. When compared to each sub-molecular type. High CDK2AP1/PTEN-loss, abnormal AR or p53 expression showed even worse association to poorer OS and CCS and remained significant when adjusted for GG. Our data indicates that CDK2AP1 directly binds to p53 using the Co-Immunoprecipitation (Co-IP) technique, which was validated using molecular docking tools. This suggests that these two proteins have a significant association through several binding features and correlates with our observed clinical data. In conclusion, our results indicated that the CDK2AP1 overexpression is associate with worse OS and CSS when combined with certain PCa molecular subtypes; interaction between p53 stands out as the most prominent candidate which directly interacts with CDK2AP1.

Loss of KLK4::KLKP1 pseudogene expression by RNA chromogenic in-situ hybridization is associated with PTEN loss and increased risk of biochemical recurrence in a cohort of middle eastern men with prostate cancer

BACKGROUND

KLK4::KLKP1 fusion is a recently described pseudogene that is enriched in prostate cancer (PCa). This new biomarker has not been characterized in the Middle Eastern population.

OBJECTIVE

To establish the incidence and prognostic value of KLK4::KLKP1 fusion in a cohort of Middle Eastern men with PCa and explore the relationship of this marker to other relevant biomarkers (PTEN, ERG, SPINK1).

DESIGN, SETTING, AND PARTICIPANTS

We interrogated a cohort of 340 Middle Eastern men with localized PCa treated by radical prostatectomy between 2005 and 2015. KLK4::KLKP1 fusion status was assessed by RNA Chromogenic in situ hybridization (CISH) and correlated to pathological and clinical parameters.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

RNA-CISH expression of KLK4::KLKP1 was correlated with prognostic factors, ERG, PTEN, and SPINK1 expression, and biochemical recurrence (BCR) following prostatectomy.

RESULTS AND LIMITATIONS

51.7% of patient samples showed positive KLK4::KLKP1 expression; more commonly in cores of PCa (38%) versus non-cancer (20.6%) (p < 0.0001) and in lower Gleason Grade Group tumors (1-3) vs (4-5). KLK4::KLKP1 expression positively correlated with ERG positivity and inversely associated with PTEN loss. No significant association was found with SPINK1 expression, seminal vesicle invasion, positive surgical margin, pathological stage, or patient age (< 50 or ≥ 50). The association between PTEN loss and BCR increased when combined with KLK4::KLKP1 negativity (HR 2.31, CI 1.03-5.20, p = 0.042).

CONCLUSIONS

KLK4::KLKP1 expression is more common in this cohort of Middle Eastern men than has been reported in North American men. It is associated with ERG positivity and inversely correlated with PTEN loss. In isolation, KLK4::KLKP1 expression was not significantly associated with clinical outcome or pathological parameters. However, its expression is associated with certain molecular subtypes (ERG-positive, PTEN-intact) and as we demonstrate may help further stratify the risk of recurrence within these groups.

The Expression of Proto-Oncogene ETS-Related Gene (ERG) Plays a Central Role in the Oncogenic Mechanism Involved in the Development and Progression of Prostate Cancer

The ETS-related gene (ERG) is proto-oncogene that is classified as a member of the ETS transcription factor family, which has been found to be consistently overexpressed in about half of the patients with clinically significant prostate cancer (PCa). The overexpression of ERG can mostly be attributed to the fusion of the ERG and transmembrane serine protease 2 (TMPRSS2) genes, and this fusion is estimated to represent about 85% of all gene fusions observed in prostate cancer. Clinically, individuals with ERG gene fusion are mostly documented to have advanced tumor stages, increased mortality, and higher rates of metastasis in non-surgical cohorts. In the current review, we elucidate ERG’s molecular interaction with downstream genes and the pathways associated with PCa. Studies have documented that ERG plays a central role in PCa progression due to its ability to enhance tumor growth by promoting inflammatory and angiogenic responses. ERG has also been implicated in the epithelial–mesenchymal transition (EMT) in PCa cells, which increases the ability of cancer cells to metastasize. In vivo, research has demonstrated that higher levels of ERG expression are involved with nuclear pleomorphism that prompts hyperplasia and the loss of cell polarity.

Analysis of the role of PI3K-AKT and DNA damage repair (DDR) genomic biomarkers as predictors of clinical outcomes in nonmetastatic castration-resistant prostate cancer (nmCRPC)

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Background: Clinically relevant outcomes in nmCRPC treated with androgen receptor-axis-targeted therapies (ARAT) may be inferior in patients with tumors harboring mutations bypassing androgen receptor signalling. This final update of a retrospective, multicenter analysis explores the association between genomic mutations in the PI3K-AKT and DDR signalling pathways with ARAT treatment outcomes in nmCRPC patients. Methods: Relevant clinical endpoint were collected for high-risk nmCRPC patients treated with an ARAT at APCaRI affiliated cancer centers, including median metastasis-free survival (MFS), overall survival (OS), PSA decline ≥ 50% (PSA50), and second progression free survival (PFS2). Archival tumor tissue was accessed for next generation gene sequencing, examining for genomic alterations in 500 genes, including those involved in the DDR and the PI3K-AKT signalling pathways. Comparison of outcomes of patients with DDR and PI3K-AKT pathway mutations was conducted using Cox proportional hazards regression using wildtype cases as the reference group, adjusting for PSA doubling time and pelvic lymphadenopathy. Results: Of the 37 patients included, 30 (82%) received apalutamide, 5 (13%) received darolutamide, and 2 (6%) received enzalutamide. 10 patients (27%) had PI3K-AKT pathway mutations (4 PTEN, 3 PIK3Ca, 2 PIK3C2G, 1 PIK3C2b), 8 patients (22%) had DDR gene mutations (3 ATM, 2 CHEK1, 1 BRCA2, 1 CDK12, 1 CHEK2, 1 FANCD2, 1 FANCL), and 1 patient (3%) had 2 MLH1 mutations (microsatellite instability). Of those who had subsequent treatment, 1 received enzalutamide and 5 received abiraterone. Patients with PI3K-AKT pathway mutations had significantly shorter MFS (4.8 mo; HR 4.2; 95% CI 1.2 – 15.0; p = 0.025). Those with DDR mutations had a trend towards shorter MFS (23.3 mo HR 3.7; 95% CI 0.71 – 13.4; p = 0.134). OS data remains immature. 4 (11%) patients did not achieve PSA50, including a patient with 2 MLH1 mutations. Conclusions: This final analysis demonstrates that nmCRPC with PI3K and DDR signalling pathway mutations have poor clinical outcomes when treated with ARAT, likely secondary to decreased reliance on the androgen receptor signalling pathway. These results highlight the potential value of exploring targeted therapies, such as PARP or AKT inhibitors in patients with these mutations.

Copy Number Profiles of Prostate Cancer in Men of Middle Eastern Ancestry

Simple Summary

Prostate cancer is the most commonly diagnosed non-skin malignancy in men. Numerous studies have been undertaken to explore the role that genomics plays in prostate cancer initiation and progression. Most of this genomic data comes tumors arising in men with European or Asian ancestry, leaving other ancestry groups understudied. To fill this gap, we investigated the differences in copy number aberrations between prostate cancers arising in men of Middle Eastern ethnicity and those of European, African, or East Asian ethnicities in the hope of better understanding the incidence and risk of prostate cancer in different populations. We identified ancestry-specific gains and deletions, as well as differences in overall genomic instability between ancestry groups. This confirms that ancestry should be considered when investigating and characterizing biomarkers and molecular signatures relative to disease progression, prognosis, and potentially therapeutic targeting.

Abstract

Our knowledge of prostate cancer (PCa) genomics mainly reflects European (EUR) and Asian (ASN) populations. Our understanding of the influence of Middle Eastern (ME) and African (AFR) ancestry on the mutational profiles of prostate cancer is limited. To characterize genomic differences between ME, EUR, ASN, and AFR ancestry, fluorescent in situ hybridization (FISH) studies for NKX3-1 deletion and MYC amplification were carried out on 42 tumors arising in individuals of ME ancestry. These were supplemented by analysis of genome-wide copy number profiles of 401 tumors of all ancestries. FISH results of NKX3-1 and MYC were assessed in the ME cohort and compared to other ancestries. Gene level copy number aberrations (CNAs) for each sample were statistically compared between ancestry groups. NKX3-1 deletions by FISH were observed in 17/42 (17.5%) prostate tumors arising in men of ME ancestry, while MYC amplifications were only observed in 1/42 (2.3%). Using CNAs called from arrays, the incidence of NKX3-1 deletions was significantly lower in ME vs. other ancestries (20% vs. 52%; p = 2.3 × 10⁻³). Across the genome, tumors arising in men of ME ancestry had fewer CNAs than those in men of other ancestries (p = 0.014). Additionally, the somatic amplification of 21 specific genes was more frequent in tumors arising in men of ME vs. EUR ancestry (two-sided proportion test; Q < 0.05). Those included amplifications in the glutathione S-transferase family on chromosome 1 (GSTM1, GSTM2, GSTM5) and the IQ motif-containing family on chromosome 3 (IQCF1, IQCF2, IQCF13, IQCF4, IQCF5, IQCF6). Larger studies investigating ME populations are warranted to confirm these observations.

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.

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.

Development and Validation of a Genomic Tool to Predict Seminal Vesicle Invasion in Adenocarcinoma of the Prostate

PURPOSE

Pretreatment estimates of seminal vesicle invasion (SVI) are challenging and significantly influence the management of prostate cancer. We sought to improve current models to predict SVI through the development of an SVI prediction genomic signature.

PATIENTS AND METHODS

A total of 15,889 patients who underwent radical prostatectomy (RP) with available baseline clinical, pathology, and transcriptome data were retrieved from the GRID registry (ClinicalTrials.gov identifier: NCT02609269) and other retrospective cohorts. These data were divided into a training (n = 6,766), test (n = 3,363), and two validation (n = 5,062 and 698) cohorts. Multivariable logistic regression was performed to assess the predictive effect of the genomic SVI (gSVI) classifier in the presence of established nomograms (Partin Tables and Memorial Sloan Kettering Cancer Center [MSKCC]).

RESULTS

In the training cohort, univariable filtering identified 2,132 genes that were differentially expressed between RP tumors with and without SVI. Model parameters were tuned to maximize the area under the curve (AUC) in the testing cohort, resulting in a logistic generalized linear model with 581 genes. The gSVI model scores range from 0 to 1. In the first validation set, gSVI showed superior discrimination of patients with and without SVI at RP compared with other prognostic signatures trained to predict distant metastasis or clinical recurrence. Of the 698 patients in the second validation set, gSVI combined with the MSKCC nomogram had a superior AUC (0.86) compared with either nomogram individually (0.81).

CONCLUSION

The gSVI represents a novel and validated expression signature to predict the presence of SVI before treatment with surgery. This genomic tool adds discriminatory power to existing clinical predictive nomograms and may help with pretreatment counseling and decision making.

Abstract 2012: Recurrent rearrangements of NAALADL2 in prostate, breast, cervical, head and neck and lung squamous cell carcinoma

Prostate cancer is a heterogeneous disease with unique molecular aberrations present in patient sub-groups. Distinct prostate cancer molecular changes have been shown to associate with specific clinical outcomes, suggesting the potential of molecular markers as diagnostic and prognostic biomarkers for prostate cancer. Recurrent ETS family gene fusions, BRAF and SPINK1 overexpression account for about 50-60% of the prostate cancer cases. Genetic aberrations in the remaining 40-50% of the cases is not known. Our attempt to identify new molecular markers in prostate cancer led to the identification of NAALADL2 gene shown to be associated with aggressive prostate cancer. In this study, we carried out a comprehensive analysis of genomic changes of NAALADL2 in prostate and other solid cancers by analyzing copy number changes and gene expression using TCGA next generation RNA sequencing data. We observed recurrent amplification, rearrangement, deletion, mutations and over-expression of NAALADL2 in prostate cancer cases. Notably, we observed mutually exclusive aberrations in NAALADL2 when compared to other cases with known prostate cancer aberrations including ETS gene fusions, indicating NAALADL2 as a distinct molecular sub-set of prostate cancer. Independent validation by fluorescent in situ hybridization (FISH) analysis using break apart probe for NAALADL2 on 874 prostate cancer revealed recurrent amplification and rearrangements in about 8% (71/874) [PN1] of the cases with higher prevalence in Caucasian American than African American cases. Based on these results, we explored prostate cancer TGCA gene fusion database and identified additional cases with gene fusions involving NAALADL2. We selected one of the gene fusions identified in the TCGA database involving NAALADL2-PIK3CA and conducted in vitro functional characterization studies and showed its oncogenic properties. Gene expression microarray analysis of RWPE1 cells transfected with NAALADL2-PIK3CA showed dysregulation of genes involved in cancer related pathways, further suggesting a role for NAALADL2-PIK3CA in prostate cancer development. Based on these studies, we explored the incidence of NAALADL2 gene fusion in other solid cancers including lung squamous cell cancer (LUSC), ovarian cancer, head and neck cancer, cervical cancer and breast cancer shown to have recurrent gene fusions identified in the TCGA gene fusion database. Notably, recurrent rearrangements and amplification are seen in a large subset (45%) of LUSC patients, but not in lung adenocarcinoma, suggesting that NAALADL2 could be developed as a novel biomarker in LUSC. Further validation studies using FISH in our independent cohort of LUSC and breast cancer patients including 79 patients from Ghana confirmed recurrent rearrangements and amplification in a subset of cases. In conclusion, similar to ERG, BRAF and FGFR genes, we show recurrent gene fusions of NAALADL2 across multiple solid cancer with potential applications as a pan cancer molecular marker for cancer diagnosis and a potential target for drug development.

Citation Format: Pavithra D. Arachchige, Shannon Carskadon, James Hu, Justin Fernando, Darshan S. Chandrashekar, Nilesh S. Gupta, Sean R. Williamson, Dhananjay A. Chitale, Craig G. Rogers, James O. Peabody, Mani Menon, Tarek A. Bismar, Evelyn Jiagge, Sooryanarayana Varambally, Nallasivam Palanisamy. Recurrent rearrangements of NAALADL2 in prostate, breast, cervical, head and neck and lung squamous cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2012.

DNA methylation signatures of Prostate Cancer in peripheral T-cells

Background

Prostate Cancer (PCa) is the second most common cancer in men where advancements have been made for early detection using imaging techniques, however these are limited by lesion size. Immune surveillance has emerged as an effective approach for early detection and to monitor disease progression. In recent studies, we have shown that host peripheral blood immune cells undergo changes in DNA methylation in liver and breast cancer.

Methods

In the current study, we examined the DNA methylation status of peripheral blood T cells of men with positive biopsy for PCa versus men with negative biopsy having benign prostate tissue, defined as controls. T cells DNA was isolated and subjected to Illumina Infinium methylation EPIC array and validated using Illumina amplicon sequencing and pyrosequencing platforms.

Results

Differential methylation of 449 CG sites between control and PCa T cell DNA showed a correlation with Gleason score (p < 0.05). Two hundred twenty-three differentially methylated CGs between control and PCa (∆ß +/− 10%, p < 0.05), were enriched in pathways involved in immune surveillance system. Three CGs which were found differentially methylated following DMP (Differentially methylated probes) analysis of ChAMP remained significant after BH (Benjamini-Hochberg) correction, of which, 2 CGs were validated. Predictive ability of combination of these 3 CGs (polygenic methylation score, PMS) to detect PCa had high sensitivity, specificity and overall accuracy. PMS also showed strong positive correlation with Gleason score and tumor volume of PCa patients.

Conclusions

Results from the current study provide for the first-time a potential role of DNA methylation changes in peripheral T cells in PCa. This non-invasive methodology may allow for early intervention and stratification of patients into different prognostic groups to reduce PCa associated morbidity from repeat invasive prostate biopsies and design therapeutic strategy to reduce PCa associated mortality.

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.

Clonal evaluation of early onset prostate cancer by expression profiling of ERG, SPINK1, ETV1, and ETV4 on whole-mount radical prostatectomy tissue

BACKGROUND

Expression profiles of erythroblast transformation-specific (ETS)-related gene fusions and serine protease inhibitor Kazal-type 1 (SPINK1) in early onset prostate cancer have not been thoroughly explored.

METHODS

We retrieved 151 radical prostatectomy specimens from young men with prostate cancer (<55 years) and characterized the expression of ETS-related gene (ERG), SPINK1, ETS Variant 1 (ETV1), and ETV4 by dual immunohistochemistry and dual RNA in situ hybridization. Age, race, family history, preoperative prostate-specific antigen, biochemical recurrence, and pathological variables using whole-mount radical prostatectomy tissue were collected.

RESULTS

A total of 313 tumor nodules from 151 men including 68 (45%) Caucasians and 61 (40%) African Americans were included in the analysis. Positive family history of prostate cancer was seen in 65 (43%) patients. Preoperative prostate-specific antigen ranged from 0.3 to 52.7 ng/mL (mean = 7.04). The follow-up period ranged from 1 to 123.7 months (mean = 30.3). Biochemical recurrence was encountered in 8 of 151 (5%). ERG overexpression was observed in 85 of 151 (56%) cases, followed by SPINK1 in 61 of 151 (40%), ETV1 in 9 of 149 (6%), and ETV4 in 4 of 141 (3%). There were 25 of 151 (17%) cases showing both ERG and SPINK1 overexpression within different regions of either the same tumor focus or different foci. Higher frequency of ERG overexpression was seen in younger patients (≤45 years old; 76% vs 49%, P = .002), Caucasian men (71% vs 41% P = .0007), organ-confined tumors (64% vs 33%, P = .0008), and tumors of Gleason Grade groups 1 and 2 (62% vs 26%, P = .009). SPINK1 overexpression was more in African American men (68% vs 26%, P = .00008), in tumors with high tumor volume (>20%) and with anterior located tumors. ETV1 and ETV4 demonstrated rare overexpression in these tumors, particularly in the higher-grade tumors.

CONCLUSION

This study expands the knowledge of the clonal evolution of multifocal cancer in young patients and support differences in relation to racial background and genetics of prostate cancer.

Case - Highly aggressive urothelial carcinoma of the bladder presenting with solitary metastasis to the phalanx

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Validation of a neuroendocrine-like classifier confirms poor outcomes in patients with bladder cancer treated with cisplatin-based neoadjuvant chemotherapy

PURPOSE

Neuroendocrine (NE)-like carcinoma is a newly recognized molecular subtype of conventional urothelial carcinoma of the bladder with transcriptomic profiles and clinical outcomes highly similar to histological NE carcinoma. The identification of NE-like tumors is challenging, as these tumors often appear histologically like urothelial carcinoma and can be missed by routine morphological criteria. We previously developed a single-sample classifier to identify NE-like tumors, which we aimed to validate in an independent cohort.

MATERIALS AND METHODS

A single-sample genomic classifier was performed on transurethral specimens from a retrospective multicenter cohort of 234 patients who underwent cisplatin-based neoadjuvant chemotherapy and subsequent radical cystectomy. Outcomes were compared for NE-like vs. non-NE-like.

RESULTS

We identified 10 patients with urothelial tumors of the NE-like subtype, all of which had robust gene expression of neuronal markers, but did not express markers associated with basal or luminal tumors. The cancer-specific mortality rates were significantly higher compared to non-NE-like tumors (P < 0.001), with 5 of the 10 patients dying within 12 months from surgery.

CONCLUSIONS

The single-sample classifier was able to identify urothelial carcinomas with NE-like subtype. These NE-like tumors have demonstrated transcriptomic profiles and clinical behavior similar to histological NE tumors across multiple patient cohorts. We propose that NE-like tumors should be managed similarly to histological NE tumors, and that standard treatments for small cell lung cancer as well as novel strategies may be evaluated in these patients.

Development of a predictive model for stromal content in prostate cancer samples to improve signature performance

Prostate cancer is heterogeneous in both cellular composition and patient outcome, and development of biomarker signatures to distinguish indolent from aggressive tumours is a high priority. Stroma plays an important role during prostate cancer progression and undergoes histological and transcriptional changes associated with disease. However, identification and validation of stromal markers is limited by a lack of datasets with defined stromal/tumour ratio. We have developed a prostate‐selective signature to estimate the stromal content in cancer samples of mixed cellular composition. We identified stromal‐specific markers from transcriptomic datasets of developmental prostate mesenchyme and prostate cancer stroma. These were experimentally validated in cell lines, datasets of known stromal content, and by immunohistochemistry in tissue samples to verify stromal‐specific expression. Linear models based upon six transcripts were able to infer the stromal content and estimate stromal composition in mixed tissues. The best model had a coefficient of determination R² of 0.67. Application of our stromal content estimation model in various prostate cancer datasets led to improved performance of stromal predictive signatures for disease progression and metastasis. The stromal content of prostate tumours varies considerably; consequently, deconvolution of stromal proportion may yield better results than tumour cell deconvolution. We suggest that adjusting expression data for cell composition will improve stromal signature performance and lead to better prognosis and stratification of men with prostate cancer. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Characterization of transcriptomic signature of primary prostate cancer analogous to prostatic small cell neuroendocrine carcinoma

Prostatic small cell neuroendocrine carcinoma (SC/NE) is well studied in metastatic castration‐resistant prostate cancer; however, it is not well characterized in the primary setting. Herein, we used gene expression profiling of SC/NE prostate cancer (PCa) to develop a 212 gene signature to identify treatment‐naïve primary prostatic tumors that are molecularly analogous to SC/NE (SC/NE‐like PCa). The 212 gene signature was tested in several cohorts confirming similar molecular profile between prostatic SC/NE and small cell lung carcinoma. The signature was then translated into a genomic score (SCGScore) using modularized logistic regression modeling and validated in four independent cohorts achieving an average AUC >0.95. The signature was evaluated in more than 25,000 primary adenocarcinomas to characterize the biology, prognosis and potential therapeutic response of predicted SC/NE‐like tumors. Assessing SCGScore in a prospective cohort of 17,967 RP and 6,697 biopsy treatment‐naïve primary tumors from the Decipher Genomic Resource Information Database registry, approximately 1% of the patients were found to have a SC/NE‐like transcriptional profile, whereas 0.5 and 3% of GG1 and GG5 patients respectively showed to be SC/NE‐like. More than 80% of these patients are genomically high‐risk based on Decipher score. Interrogating in vitro drug sensitivity analyses, SC/NE‐like prostatic tumors showed higher response to PARP and HDAC inhibitors.

What's new?

While genomic/transcriptomic data analysis has revolutionized cancer biology, this analysis is frequently only available late in the cancer history, often after years of therapy. Here the authors built a single sample genomic classifier to predict primary prostate cancer tumors with early small cell neuroendocrine differentiation. They show in three independent cohorts that small cell neuroendocrine tumors of the prostate are similar to small cell tumors of the lung and predict the specific prostate tumors to be responsive to inhibitors of poly ADP ribose polymerase and histone deacetylases, underscoring the use of these drugs in this subtype of prostate cancer.

Genomic Characterization of Prostatic Ductal Adenocarcinoma Identifies a High Prevalence of DNA Repair Gene Mutations

PURPOSE

Ductal prostate cancer (dPC) is a rare variant of prostatic adenocarcinoma associated with poor outcomes. Although its histopathologic features are well characterized, the underlying molecular hallmarks of this aggressive subtype are not well described. We sought to provide a comprehensive overview of the spectrum of mutations associated with dPC.

METHODS

Three case series across multiple institutions were assembled. All patients had a diagnosis of dPC, and histopathologic classification was confirmed by an expert genitourinary pathologist. Case series 1 included men who were prospectively enrolled in a tumor sequencing study at the University of Washington (n = 22). Case series 2 and 3 included archival samples from men treated at Johns Hopkins Hospital (n = 21) and University of Calgary (n = 8), respectively. Tumor tissue was sequenced on a targeted next-generation sequencing assay, UW-OncoPlex, according to previously published methods. The frequency of pathogenic/likely pathogenic mutations are reported.

RESULTS

Overall, 25 patients (49%) had at least one DNA damage repair gene alteration, including seven (14%) with a mismatch repair gene mutation and 16 (31%) with a homologous repair mutation. Germline autosomal dominant mutations were confirmed or suspected in 10 patients (20%). Activating mutations in the PI3K pathway (n = 19; 37%), WNT pathway (n = 16; 31%), and MAPK pathway (n = 8; 16%) were common.

CONCLUSION

This study strongly suggests that dPCs are enriched for actionable mutations, with approximately 50% of patients demonstrating DNA damage repair pathway alteration(s). Patients with dPC should be offered next-generation sequencing to guide standard-of-care treatment (eg, immune checkpoint inhibitors) or triaged toward an appropriate clinical trial (eg, poly [ADP-ribose] polymerase inhibitors).

Expression of IGF/insulin receptor in prostate cancer tissue and progression to lethal disease

Circulating insulin-like growth factor-1 (IGF-1) is consistently associated with prostate cancer risk. IGF-1 binds to IGF-1 receptor (IGF1R) and insulin receptor (IR), activating cancer hallmark pathways. Experimental evidence suggests that TMPRSS2:ERG may interact with IGF/insulin signaling to influence progression. We investigated IGF1R and IR expression and its association with lethal prostate cancer among 769 men. Protein expression of IGF1R, IR and ERG (i.e. a surrogate of ERG fusion genes) were assayed by immunohistochemistry. Cox models estimated hazard ratios (HR) and 95% confidence intervals (CI) adjusted for clinical characteristics. Among patients, 29% had strong tumor IGF1R expression and 10% had strong IR expression. During a mean follow-up of 13.2 years through 2012, 80 men (11%) developed lethal disease. Tumors with strong IGF1R or IR expression showed increased cell proliferation, decreased apoptosis and a higher prevalence of ERG. In multivariable models, strong IGF1R was associated with a borderline increased risk of lethal prostate cancer (HR 1.7; 95% CI 0.9-3.1). The association appeared greater in ERG-positive tumors (HR 2.8; 95% CI 0.9-8.4) than in ERG-negative tumors (HR 1.3; 95% CI 0.6-3.0, p-heterogeneity 0.08). There was no association between IR and lethal prostate cancer (HR 0.8; 95% CI 0.4-1.9). These results suggest that tumor IGF1R expression may play a role in prostate cancer progression to a lethal phenotype and that ERG-positive tumors may be more sensitive to IGF signaling. These data may improve our understanding of IGF signaling in prostate cancer and suggest therapeutic options for disease subtypes.

Clinical utility of assessing PTEN and ERG protein expression in prostate cancer patients: a proposed method for risk stratification

OBJECTIVES

To assess the prognostic value of ERG and PTEN protein expression as two of the most common genetic aberration in men with prostate cancer managed non-surgically by androgen deprivation therapy (ADT).

MATERIALS AND METHODS

463 tumor samples were assessed by double immunohistochemistry stains for ERG and PTEN and data correlated with clinical pathological features including, Gleason score, patients' outcome and ADT.

RESULTS

ERG expression and PTEN protein loss were present in 28.2% and 38% of total patients respectively. There was a significant interplay between ERG and PTEN expression with 21.8% PTEN negative tumors being ERG positive (p < 0.001). Both ERG and PTEN showed significant association with lethal disease in all patients and those treated with prior ADT representing castrate-resistant disease. However, only PTEN remained significant in multivariable proportional hazards regression analysis, when including Gleason score and patients' age. Depending on patient's subgroup, intact positive PTEN intensity showed better cancer-specific survival with HR ranging from 0.25 to 0.4 compared to tumors with loss of PTEN expression. Assessing combined marker status, patients with decreased PTEN intensity without ERG positivity showed the worst clinical outcome compared to those with no PTEN loss and no ERG expression, where they had best clinical outcome. Patients with ERG expression with or without PTEN loss showed intermediate risk in relation to lethal disease.

CONCLUSION

This study confirms a significant prognostic role for assessing ERG and PTEN in men with prostate cancer. It supports a role for utilizing combined ERG/PTEN status clinically and prospectively for stratifying PCa patients into different prognostic groups.

Quantitative in vivo whole genome motility screen reveals novel therapeutic targets to block cancer metastasis

Metastasis is the most lethal aspect of cancer, yet current therapeutic strategies do not target its key rate-limiting steps. We have previously shown that the entry of cancer cells into the blood stream, or intravasation, is highly dependent upon in vivo cancer cell motility, making it an attractive therapeutic target. To systemically identify genes required for tumor cell motility in an in vivo tumor microenvironment, we established a novel quantitative in vivo screening platform based on intravital imaging of human cancer metastasis in ex ovo avian embryos. Utilizing this platform to screen a genome-wide shRNA library, we identified a panel of novel genes whose function is required for productive cancer cell motility in vivo, and whose expression is closely associated with metastatic risk in human cancers. The RNAi-mediated inhibition of these gene targets resulted in a nearly total (>99.5%) block of spontaneous cancer metastasis in vivo.

Tumour metastasis is dependent on tumour cell motility. Here, the authors investigate genes required for tumour cell motility by establishing a quantitative in vivo screening platform based on intravital imaging of human cancer metastasis in ex ovo avian embryos.

Validation of a genomic classifier to predict adverse pathology in men diagnosed with low risk prostate cancer

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Background: The Decipher 22-feature genomic classifier (GC) has been validated to predict metastasis and prostate cancer specific mortality in needle biopsy (Bx) tissue of men with intermediate and high-risk prostate cancer. We validate GC in diagnostic Bx specimens for the prediction of high-grade/stage (HGS) disease at radical prostatectomy (RP) in men with low and favorable-intermediate (fav-int) NCCN risk group disease. Methods: We identified 176 men diagnosed with low or fav-int NCCN risk group disease who had available Bx GC scores and pathological information after RP from Cedars-Sinai, University of Calgary, Cleveland Clinic, MD Anderson, and Johns Hopkins. The GC score was calculated based on a locked random forest model. Scores range from 0-1 with cut points for GC low, intermediate and high risk groups as <0.45, 0.45-0.6, and >0.6, respectively. The primary endpoint was HGS (Gleason group 3-5 or pT3b or lymph node invasion (LNI)). Univariable (UVA) and multivariable (MVA) logistic regression models were used to evaluate GC and CAPRA. Results: Median age of the cohort was 62 years, 87% and 13% had Bx grade group (GG) 1 or 2 disease. 76% and 24% were NCCN low and fav-int risk, respectively. CAPRA classified 70% as low (0-2) and 30% as average risk (3-5). GC classified 80% low, 16% intermediate and 4% high genomic risk. After RP, 41% had RP GG 1, 46% GG 2 and 13% had GG 3-5 disease. pT3b or positive lymph nodes were observed in 7 men (4%), overall 27 (15%) of men had HGS at RP. In the UVA and MVA, GC was the only significant predictor of HGS with odds ratio (OR) of 1.38 and 1.34 per 10% unit increase, before and after adjusting for CAPRA (p=0.011, 0.027). A low risk score (GC<0.45) had a negative predictive value (NPV) of 92% to identify men who do not have HGS at RP. In exploratory analysis, a very low risk cut-point (GC<0.2) was found which had a sensitivity of 96% and an NPV of 99%. 26% of men had GC<0.2. Conclusions: We validated GC in a multi-institutional study to predict HGS at RP among men with NCCN low and fav-int risk disease with high sensitivity and NPV. Future studies will aim to validate the very low risk genomic cut-point to guide decision-making and follow-up biopsy protocols for men considering or in active surveillance.

ING3 promotes prostate cancer growth by activating the androgen receptor

BACKGROUND

The androgen receptor (AR) is a major driver of prostate cancer, and increased AR levels and co-activators of the receptor promote the development of prostate cancer. INhibitor of Growth (ING) proteins target lysine acetyltransferase or lysine deacetylase complexes to the histone H3K4Me3 mark of active transcription, to affect chromatin structure and gene expression. ING3 is a stoichiometric member of the TIP60 lysine acetyltransferase complex implicated in prostate cancer development.

METHODS

Biopsies of 265 patients with prostate cancer were stained for ING3, pan-cytokeratin, and DNA. LNCaP and C4-2 androgen-responsive cells were used for in vitro assays including immunoprecipitation, western blotting, Luciferase reporter assay and quantitative polymerase chain reaction. Cell viability and migration assays were performed in prostate cancer cell lines using scrambled siRNA or siRNA targeting ING3.

RESULTS

We find that ING3 levels and AR activity positively correlate in prostate cancer. ING3 potentiates androgen effects, increasing expression of androgen-regulated genes and androgen response element-driven reporters to promote growth and anchorage-independent growth. Conversely, ING3 knockdown inhibits prostate cancer cell growth and invasion. ING3 activates the AR by serving as a scaffold to increase interaction between TIP60 and the AR in the cytoplasm, enhancing receptor acetylation and translocation to the nucleus. Activation is independent of ING3's ability to target the TIP60 complex to H3K4Me3, identifying a previously unknown chromatin-independent cytoplasmic activity for ING3. In agreement with in vitro observations, analysis of The Cancer Genome Atlas (TCGA) data (n = 498) and a prostate cancer tissue microarray (n = 256) show that ING3 levels are higher in aggressive prostate cancers, with high levels of ING3 predicting shorter patient survival in a low AR subgroup. Including ING3 levels with currently used indicators such as the Gleason score provides more accurate prognosis in primary prostate cancer.

CONCLUSIONS

In contrast to the majority of previous reports suggesting tumor suppressive functions in other cancers, our observations identify a clear oncogenic role for ING3, which acts as a co-activator of AR in prostate cancer. Data from TCGA and our previous and current tissue microarrays suggest that ING3 levels correlate with AR levels and that in patients with low levels of the receptor, ING3 level could serve as a useful prognostic biomarker.

Tubulovillous Adenoma in the Bladder in a Dual Pancreas-Kidney Transplant Patient

Background: A rare report of a tubulovillous adenoma arising in the setting of a dual pancreas-kidney transplant patient.

Case Presentation: This adenoma was discovered in a 60-year-old male with a dual pancreas-kidney transplant that presented with urinary retention and gross hematuria. Management of this patient required both transurethral resection of the tumor as well as a laparotomy after recurrence. Follow-up with cystoscopy has shown no further recurrence of the tumor.

Conclusion: This case adds to the few cases documented of adenomas arising in bladders augmented with gastrointestinal tract tissue. The tumor may reflect growth from donor duodenal graft tissue, however, the metaplasia of urothelial tissue cannot be fully ruled out. Based on this case, our understanding of these rare tumors and their clinical course is deepened.

SPINK1 Overexpression in Localized Prostate Cancer: a Rare Event Inversely Associated with ERG Expression and Exclusive of Homozygous PTEN Deletion

SPINK1 is proposed as potential prognostic marker in prostate cancer (PCA). However, its relation to PTEN and ERG in localized PCA remains unclear. The study population consisted of two independent cohorts of men treated by radical prostatectomy for localized PCA (discovery n = 218 and validation n = 129). Patterns of association between SPINK1 and each of ERG and PTEN were evaluated by immunohistochemistry and fluorescence in situ hybridization. Associations between SPINK1 expression and various pathologic parameters and clinical outcome were also investigated. SPINK1 was expressed in 15.3 % and 10.9 % of cases in the discovery and validation cohort, respectively. SPINK expression was observed in 5.56 % of high-grade prostatic intraepithelial neoplasia and 1.1 % of adjacent morphologically benign prostatic glands. SPINK1 and ERG expression were almost exclusive, with only 1.0 % of the cases co-expressing both in the same core sample. SPINK1 interfocal and within-core heterogeneity was noted in 29.2 % and 64.6 % of cases, respectively. SPINK1 expression was not significantly associated with PTEN deletion in the two cohorts (p = 0.871 for discovery cohort and p = 0.293 for validation cohort). While SPINK1 expression did occur with hemizygous PTEN deletion, there was a complete absence of SPINK1 expression in PCA showing homozygous PTEN deletion, which was confirmed in the validation cohort (p = 0.02). Despite SPINK1's association with higher Gleason score (>7) (p = 0.02), it was not associated with other pathological parameters or biochemical recurrence post-radical prostatectomy. We documented absolute exclusivity between SPINK1 overexpression and homozygous PTEN deletion in localized PCA. SPINK1 and ERG expressions are exclusive events in PCA. SPINK1 is not of added prognostic value in localized PCA.

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.

Neural Cell Adhesion Protein CNTN1 Promotes the Metastatic Progression of Prostate Cancer

Prostate cancer metastasis is the main cause of disease-related mortality. Elucidating the mechanisms underlying prostate cancer metastasis is critical for effective therapeutic intervention. In this study, we performed gene-expression profiling of prostate cancer stem-like cells (PCSC) derived from DU145 human prostate cancer cells to identify factors involved in metastatic progression. Our studies revealed contactin 1 (CNTN1), a neural cell adhesion protein, to be a prostate cancer-promoting factor. CNTN1 knockdown reduced PCSC-mediated tumor initiation, whereas CNTN1 overexpression enhanced prostate cancer cell invasion in vitro and promoted xenograft tumor formation and lung metastasis in vivo. In addition, CNTN1 overexpression in DU145 cells and corresponding xenograft tumors resulted in elevated AKT activation and reduced E-cadherin (CDH1) expression. CNTN1 expression was not readily detected in normal prostate glands, but was clearly evident on prostate cancer cells in primary tumors and lymph node and bone metastases. Tumors from 637 patients expressing CNTN1 were associated with prostate cancer progression and worse biochemical recurrence-free survival following radical prostatectomy (P < 0.05). Collectively, our findings demonstrate that CNTN1 promotes prostate cancer progression and metastasis, prompting further investigation into the mechanisms that enable neural proteins to become aberrantly expressed in non-neural malignancies.

SPINK1 expression in relation to PTEN and ERG in matched primary and lymph node metastatic prostate cancer: Implications for biomarker development

BACKGROUND

SPINK1, ERG, and PTEN are proposed prognostic biomarkers in prostate cancer (PCA). However, their relations and patterns of expression in primary and metastatic lymph node (LN) PCAs are not fully explored.

METHODS

A tissue microarray of matched primary PCA and LN metastasis was constructed from 36 patients. SPINK1, ERG, and PTEN expression statuses were assessed by immunohistochemistry and correlated with each other.

RESULTS

SPINK1 and ERG were expressed in 25% and 42.7% of primary PCA cases, respectively. PTEN loss of any degree was observed in 91.7% of primary PCA cases, with 54.2% showing complete loss. In primary PCA, 12.5% of the cases showed SPINK1+/ERG-phenotype, 16.7% showed SPINK1+/ERG+phenotype, 25.0% showed SPINK1-/ERG+phenotype, and 45.8% showed SPINK1-/ERG-phenotype. All PCAs with expression of either SPINK1 or ERG also exhibited PTEN loss, whereas PCA without PTEN loss (2 cases) expressed neither SPINK1 nor ERG. In primary PCA, evaluation of combined ERG and SPINK1 status, but not SPINK1 individually, was associated with a significant difference in proportion of Gleason patterns (P = 0.013), with the SPINK1+/ERG+and SPINK1-/ERG-phenotypes represented more in Gleason pattern>7 PCAs. In LN metastases, the overall SPINK1 protein expression frequency was significantly lower (6.5% of cases) compared with primary PCA (P = 0.03). Only 16.7% of cases with positive SPINK1 expression in primary PCA maintained expression in LN metastases. The down-regulated SPINK1 expression in LN was primarily because of a reduction in the SPINK1+/ERG+PCA subpopulation to 3.5% of cases (P = 0.16 compared with primary PCA). The frequencies of ERG expression and PTEN loss were relatively stable in primary PCA and LN metastases.

CONCLUSION

SPINK1 expression is dynamically regulated with up-regulation in primary sites of nodal metastatic PCA and down-regulation in LN metastases. The increased SPINK1 expression in primary site of nodal metastatic PCA is secondary to an increased frequency of SPINK1+/ERG+tumors. In primary PCAs, the SPINK1+/ERG+phenotype is associated with higher Gleason grade, suggesting that this phenotype may mark a more aggressive PCA subpopulation with higher risk of LN metastases.

ING3 protein expression profiling in normal human tissues suggest its role in cellular growth and self-renewal

Members of the INhibitor of Growth (ING) family of proteins act as readers of the epigenetic code through specific recognition of the trimethylated form of lysine 4 of histone H3 (H3K4Me3) by their plant homeodomains. The founding member of the family, ING1, was initially identified as a tumor suppressor with altered regulation in a variety of cancer types. While alterations in ING1 and ING4 levels have been reported in a variety of cancer types, little is known regarding ING3 protein levels in normal or transformed cells due to a lack of reliable immunological tools. In this study we present the characterization of a new monoclonal antibody we have developed against ING3 that specifically recognizes human and mouse ING3. The antibody works in western blots, immunofluorescence, immunoprecipitation and immunohistochemistry. Using this antibody we show that ING3 is most highly expressed in small intestine, bone marrow and epidermis, tissues in which cells undergo rapid proliferation and renewal. Consistent with this observation, we show that ING3 is expressed at significantly higher levels in proliferating versus quiescent epithelial cells. These data suggest that ING3 levels may serve as a surrogate for growth rate, and suggest possible roles for ING3 in growth and self renewal and related diseases such as cancer.

The prognostic significance of combined ERG and androgen receptor expression in patients with prostate cancer managed by androgen deprivation therapy

ERG and androgen receptor (AR) are known to function cooperatively in prostate cancer (PCa) progression. However, the prognostic value of combined ERG and AR expression and potential pathways are not well characterized. We assessed ERG and AR protein expression by immunohistochemistry in a cohort of 312 men with PCa diagnosed by transurethral resection of the prostate (TURP). Patients were divided into those with no prior hormonal treatment (designated as PCa/AdvPCa) vs. those with castrate-resistant PCa (CRPC) undergoing channel TURP to relieve obstructive symptoms. The expression status was correlated with various clinical-pathological parameters. The Swedish watchful-waiting cohort was used for validation and characterization of potential gene signatures associated with ERG and AR.   Patients with combined ERG-positive/AR high expression profile demonstrated higher rates of PCa-specific mortality (PCSM) compared with patients with ERG-negative/AR low in patients with no prior treatment (n = 90, P = 0.032), but this was attenuated in the overall cohort which included the CRPC subgroup (n = 125, P = 0.096). The prognostic significance to PCSM was validated in the Swedish watchful waiting cohort in univariate (HR: 3.3; 95% CI: 1.9-5.6, P = 4.25E-5) and multivariate analysis (HR: 2; 95% CI: 0.97-4.1, P = 0.057), which included Gleason score. ERG/AR overexpression status characterized 152 genes signatures including WNT, PI3K/AKT and chemokine signaling pathways known to be deregulated in PCa. In conclusion, combined ERG/AR overexpression signifies a class of patients at highest-risk of PCSM with specific key genetic alteration likely responsible for disease progression. The prognostic value of combined ERG/AR overexpression and its associated genes should be further investigated as potential prognostic and therapeutic targets in prostate cancer progression.

ERG expression is associated with increased risk of biochemical relapse following radical prostatectomy in early onset prostate cancer

PURPOSE

ERG expression has been proposed to signify molecular subtype of PCA. However, its significance in early onset prostate cancer (PCA) is not characterized.

MATERIALS AND METHODS

ERG protein expression was investigated in a cohort of 121 men diagnosed with localized PCA at <50 years of age with a mean follow-up time of 65.7 months. ERG was correlated to patients' outcome and clinical-pathological parameters using univariate and multivariate analysis.

RESULTS

ERG expression was detected in 76/118 (64.4 %) analyzable patients' samples and showed interfocal heterogeneity (differences between foci) in 17/118 (14.4 %) patients. There was significant association between ERG expression and Gleason score (p = 0.022), but not with any other clinical-pathologic parameter, including pre-surgical PSA levels, tumor volume, pathological stage, surgical margin or lymph-vascular invasion. ERG had significant effect on the rate of biochemical relapse following radical prostatectomy, with ERG positive patients showing higher relapse rates vs. ERG negative patients (p = 0.007). However, considering time till biochemical relapse post-radical prostatectomy, ERG expression showed positive insignificant trends (p = 0.071). Notably, and of great significance, in this cohort of early onset disease, none of the ERG negative PCA patients exhibited biochemical relapse.

CONCLUSION

The study results suggest that ERG expression may be of added prognostic value in localized prostate cancer in patients with early onset PCA. However, the issue of ERG interfocal heterogeneity observed may require the evaluation of several tumor foci to assess ERG status per case. Incorporating ERG status into existing nomograms may be of added prognostic value in patients with early onset PCA.

Prostate epithelium-specific deletion of the selenocysteine tRNA gene Trsp leads to early onset intraepithelial neoplasia

Although various lines of evidence suggest that oxidative stress plays a role in human prostate cancer initiation and progression, there is a paucity of direct evidence for its role in tumor initiation. To begin to address this issue, we developed a novel tumorigenesis model by reducing the expression of multiple selenoproteins (SPs) in mouse prostatic epithelium. This was accomplished via the prostate-specific deletion of Trsp, a gene that encodes a transfer RNA (Sec tRNA) required for the insertion of selenocysteine residues into SPs during their translation. By 6 weeks of age, Trsp-deficient mice exhibited widespread prostatic intraepithelial neoplasia lesions in all prostatic lobes, which then progressed to high-grade dysplasia and microinvasive carcinoma by 24 weeks. In contrast to other murine prostate cancer models, Trsp-deficient mice required neither the deletion of a tumor suppressor nor the transgenic introduction of an oncogene for prostatic intraepithelial neoplasia lesion development. In keeping with the antioxidant functions of several SPs, we found increases in lipid peroxidation markers in Trsp-deficient epithelial cells. This novel model of prostate neoplasia provides evidence for the existence of a selenoprotein or selenoproteins capable of acting as a tumor suppressor in the murine prostate.

Coordinate microRNA-mediated regulation of protein complexes in prostate cancer

MicroRNAs are a class of small non-coding regulatory RNA molecules that regulate mRNAs post-transcriptionally. Recent evidence has shown that miRNAs target entire functionally related proteins such as protein complexes and biological pathways. However, characterizing the influence of miRNAs on genes whose encoded proteins are part of protein complexes has not been studied in the context of disease. We propose an entropy-based framework to identify miRNA-mediated dysregulation of functionally related proteins during prostate cancer progression. The proposed framework uses experimentally verified miRNA-target interactions, functionally related proteins and expression data to identify miRNA-influenced protein complexes in prostate cancer, and identify genes that are dysregulated as a result. The framework constructs correlation matrixes between functionally related proteins and miRNAs that have targets in the complex, and assesses the changes in the Shannon entropy of the modules across different stages of prostate cancer. Results reveal that SMAD4 and HDAC containing protein complexes are highly affected and disrupted by miRNAs, particularly miRNA-1 and miRNA-16. Using biological pathways to define functionally related proteins reveals that NF-kB-, RAS-, and Syndecan-mediated pathways are dysregulated due to miRNA-1- and miRNA-16-mediated regulation. These results suggest that miRNA-1 and miRNA-16 are important master regulators of miRNA-mediated regulation in prostate cancer. Moreover, results reveal that miRNAs with high-influence on the disrupted protein complexes are diagnostic and prognostic biomarker candidates for prostate cancer progression. The observation of miRNA-mediated protein complex regulation and miRNA-mediated pathway regulation, with partial experimental verification from previous studies, demonstrates that our framework is a promising approach for the identification of novel miRNAs and protein complexes related to disease progression.

The significance of dynamin 2 expression for prostate cancer progression, prognostication, and therapeutic targeting

Dynamin 2 (Dyn2) is essential for intracellular vesicle formation and trafficking, cytokinesis, and receptor endocytosis. In this study, we investigated the implication of Dyn2 as a prognostic marker and therapeutic target for progressive prostate cancer (PCA). We evaluated Dyn2 protein expression by immunohistochemistry in two cohorts: men with localized PCA treated by retropubic radical prostatectomy (n = 226), and men with advanced/castrate-resistant PCA (CRPC) treated by transurethral resection of prostate (TURP) (n = 253). The role of Dyn2 in cell invasiveness was assessed by in vitro and in vivo experiments using androgen-responsive and refractory PCA preclinical models. Dyn2 expression was significantly increased across advanced stages of PCA compared to benign prostate tissue (P < 0.0001). In the CRPC cohort, high Dyn2 was associated with higher Gleason score (P = 0.004) and marginally with cancer-specific mortality (P = 0.052). In preclinical models, Dyn2 gene silencing significantly reduced cell migration and invasion in vitro, as well as tumor size and lymph node metastases in vivo. In isolated PCA cells, Dyn2 was found to regulate focal adhesion turnover, which is critical for cell migration; this mechanism requires full Dyn2 compared to mutants deficient in GTPase activity. In conclusion, Dyn2 overexpression is associated with neoplastic prostate epithelium and is associated with poor prognosis. Inhibition of Dyn2 prevents cell invasiveness in androgen-responsive and -refractory PCA models, supporting the potential benefit of Dyn2 to serve as a therapeutic target for advanced PCA.

Role of the EphB2 receptor in autophagy, apoptosis and invasion in human breast cancer cells

The Eph and Ephrin proteins, which constitute the largest family of receptor tyrosine kinases, are involved in normal tissue development and cancer progression. Here, we examined the expression and role of the B-type Eph receptor EphB2 in breast cancers. By immunohistochemistry using a progression tissue microarray of human clinical samples, we found EphB2 to be expressed in benign tissues, but strongly increased in cancers particularly in invasive and metastatic carcinomas. Subsequently, we found evidence that EphB2, whose expression varies in established cell breast lines, possesses multiple functions. First, the use of a DOX-inducible system to restore EphB2 function to low expressers resulted in decreased tumor growth in vitro and in vivo, while its siRNA-mediated silencing in high expressers increased growth. This function involves the onset of apoptotic death paralleled by caspases 3 and 9 activation. Second, EphB2 was also found to induce autophagy, as assessed by immunofluorescence and/or immunoblotting examination of the LC3, ATG5 and ATG12 markers. Third, EphB2 also has a pro-invasive function in breast cancer cells that involves the regulation of MMP2 and MMP9 metalloproteases and can be blocked by treatment with respective neutralizing antibodies. Furthermore, EphB2-induced invasion is kinase-dependent and is impeded in cells expressing a kinase-dead mutant EphB2. In summary, we identified a mechanism involving a triple role for EphB2 in breast cancer progression, whereby it regulates apoptosis, autophagy, and invasion.

Urinary bladder melanosis associated with urothelial dysplasia and invasive urothelial carcinoma: a report of two cases

BACKGROUND

Melanosis is defined as an abnormal or excessive deposition of melanin within cells and/or tissues. It typically presents as a cutaneous or buccal mucosal lesion, but rare cases of bladder melanosis have also been documented. Melanosis of the urinary bladder is typically considered a benign condition, but it has also been described in association with malignant melanoma and urothelial carcinoma.

CASES

We report the cases of 2 patients who presented with melanosis of the urinary bladder. One patient presented with melanosis of the urinary bladder together with urothelial dysplasia. Melanosis was incidentally identified during a cystoscopy for ureteral stones. A second patient presented with hematuria and was found to have a muscle invasive urothelial carcinoma with focal small nested morphology together with melanosis. We also present a literature review of the bladder melanosis and an overview of other bladder melanocytic lesions, which include primary and metastatic melanoma and blue nevus.

CONCLUSION

Initial evaluation for bladder melanosis should include cystoscopy and upper urinary tract imaging. Biopsy is essential to establish the diagnosis and rule out associated malignancy.

Protein expression of PTEN, insulin-like growth factor I receptor (IGF-IR), and lethal prostate cancer: a prospective study

BACKGROUND

Loss of PTEN has been shown to be associated with aggressive behavior of prostate cancer. It is less clear that loss of PTEN also increases the risk of cancer mortality. We investigated the association between PTEN expression and prostate cancer mortality and the potential effect modification by IGF-IR, a direct activator of the phosphoinositide-3-kinase (PI3K) pathway.

METHODS

Protein expression in tumor was evaluated using tumor tissues obtained from 805 participants of the Physicians' Health and the Health Professionals Follow-up studies who were diagnosed with prostate cancer and underwent radical prostatectomy. Proportional hazard models were used to assess PTEN expression and its interaction with IGF-IR, in relation to lethal prostate cancer (cancer-specific death or distant metastases).

RESULTS

Low PTEN expression was associated with an increased risk of lethal prostate cancer [HR, 1.7; 95% confidence interval (CI), 0.98-3.2; Ptrend = 0.04]. The association was attenuated after adjustment for Gleason grade, tumor stage, and prostate-specific antigen (PSA) at diagnosis. A significant negative interaction between PTEN and IGF-IR was found (Pinteraction = 0.03). Either reduction in PTEN or increase in IGF-IR expression was sufficient to worsen prognosis. Models including PTEN and IGF-IR expression offer additional predicting power to prostate cancer survival, compared to those only including demographic and clinical factors.

CONCLUSIONS

Low PTEN protein expression significantly increases the risk of lethal prostate cancer, particularly when the IGF-IR expression remains at normal level.

IMPACT

PTEN and IGF-IR expression in tumor are promising candidates for independent prognostic factors to predict lethal prostate cancer.