Explore the vast range of titles available.

Epigenetic regulators represent a promising new class of therapeutic targets for cancer. Enhancer of zeste homolog 2 (EZH2), a subunit of Polycomb repressive complex 2 (PRC2), silences gene expression via its histone methyltransferase activity. We found that the oncogenic function of EZH2 in cells of castration-resistant prostate cancer is independent of its role as a transcriptional repressor. Instead, it involves the ability of EZH2 to act as a coactivator for critical transcription factors including the androgen receptor. This functional switch is dependent on phosphorylation of EZH2 and requires an intact methyltransferase domain. Hence, targeting the non-PRC2 function of EZH2 may have therapeutic efficacy for treating metastatic, hormone-refractory prostate cancer.

ObjectivesThe interaction between the immune system and tumor cells is an important feature for the prognosis and treatment of cancer. Multiplex immunohistochemistry (mIHC) and multiplex immunofluorescence (mIF) analyses are emerging technologies that can be used to help quantify immune cell subsets, their functional state, and their spatial arrangement within the tumor microenvironment.MethodsThe Society for Immunotherapy of Cancer (SITC) convened a task force of pathologists and laboratory leaders from academic centers as well as experts from pharmaceutical and diagnostic companies to develop best practice guidelines for the optimization and validation of mIHC/mIF assays across platforms.ResultsRepresentative outputs and the advantages and disadvantages of mIHC/mIF approaches, such as multiplexed chromogenic IHC, multiplexed immunohistochemical consecutive staining on single slide, mIF (including multispectral approaches), tissue-based mass spectrometry, and digital spatial profiling are discussed.ConclusionsmIHC/mIF technologies are becoming standard tools for biomarker studies and are likely to enter routine clinical practice in the near future. Careful assay optimization and validation will help ensure outputs are robust and comparable across laboratories as well as potentially across mIHC/mIF platforms. Quantitative image analysis of mIHC/mIF output and data management considerations will be addressed in a complementary manuscript from this task force.

Pier Paolo Pandolfi and colleagues report that compound loss of Pten with Zbtb7a or Trp53 leads to de novo resistance to androgen deprivation therapy in prostate cancer. Integrative analysis of mouse and human data in a co-clinical approach identified XIAP and SRD5A1 inhibitors as potential therapies for castration-resistant prostate cancer. Here we report an integrated analysis that leverages data from treatment of genetic mouse models of prostate cancer along with clinical data from patients to elucidate new mechanisms of castration resistance. We show that castration counteracts tumor progression in a Pten loss–driven mouse model of prostate cancer through the induction of apoptosis and proliferation block. Conversely, this response is bypassed with deletion of either Trp53 or Zbtb7a together with Pten , leading to the development of castration-resistant prostate cancer (CRPC). Mechanistically, the integrated acquisition of data from mouse models and patients identifies the expression patterns of XAF1, XIAP and SRD5A1 as a predictive and actionable signature for CRPC. Notably, we show that combined inhibition of XIAP, SRD5A1 and AR pathways overcomes castration resistance. Thus, our co-clinical approach facilitates the stratification of patients and the development of tailored and innovative therapeutic treatments.

One of the central goals of human genetics is to discover the genes and pathways driving human traits. To date, most of the common risk alleles discovered through genome-wide association studies (GWAS) map to nonprotein-coding regions. Because of our relatively poorer understanding of this part of the genome, the functional consequences of trait-associated variants pose a considerable challenge. To identify the genes through which risk loci act, we hypothesized that the risk variants are regulatory elements. For each of 12 known risk polymorphisms, we evaluated the correlation between risk allele status and transcript abundance for all annotated protein-coding transcripts within a 1-Mb interval. A total of 103 transcripts were evaluated in 662 prostate tissue samples [normal (n = 407) and tumor (n = 255)] from 483 individuals [European Americans (n = 233), Japanese (n = 127), and African Americans (n = 123)]. In a pooled analysis, 4 of the 12 risk variants were strongly associated with five transcripts (NUDT11 , MSMB , NCOA4 , SLC22A3 , and HNF1B) in histologically normal tissue (P ≤ 0.001). Although associations were also observed in tumor tissue, they tended to be more attenuated. Previously, we showed that MSMB and NCOA4 participate in prostate cancer pathogenesis. Suppressing the expression of NUDT11 , SLC22A3 , and HNF1B influences cellular phenotypes associated with tumor-related properties in prostate cancer cells. Taken together, the data suggest that these transcripts contribute to prostate cancer pathogenesis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

While fibroblast growth factor receptor 3 (FGFR3) is frequently mutated or overexpressed in nonmuscle‐invasive urothelial carcinoma (UC), the prevalence of FGFR3 protein expression and mutation remains unknown in muscle‐invasive disease. FGFR3 protein and mRNA expression, mutational status, and copy number variation were retrospectively analyzed in 231 patients with formalin‐fixed paraffin‐embedded primary UCs, 33 metastases, and 14 paired primary and metastatic tumors using the following methods: immunohistochemistry, NanoString nCounterTM, OncoMap or Affymetrix OncoScanTM array, and Gain and Loss of Analysis of DNA and Genomic Identification of Significant Targets in Cancer software. FGFR3 immunohistochemistry staining was present in 29% of primary UCs and 49% of metastases and did not impact overall survival (P = 0.89, primary tumors; P = 0.78, metastases). FGFR3 mutations were observed in 2% of primary tumors and 9% of metastases. Mutant tumors expressed higher levels of FGFR3 mRNA than wild‐type tumors (P < 0.001). FGFR3 copy number gain and loss were rare events in primary and metastatic tumors (0.8% each; 3.0% and 12.3%, respectively). FGFR3 immunohistochemistry staining is present in one third of primary muscle‐invasive UCs and half of metastases, while FGFR3 mutations and copy number changes are relatively uncommon. Fibroblast growth factor receptor 3 (FGFR3) is frequently mutated or overexpressed in nonmuscle‐invasive urothelial carcinoma (UC) where mutations are generally associated with lower rates of progression to invasive disease. In this report, we demonstrate that FGFR3 staining is present in nearly one third of muscle‐invasive UC and half of metastases (albeit at low levels), but IHC detection of FGFR3 does not appear to impact overall survival. While the FGFR3 mutation rate is less than 10% in our population, mutant tumors had an increase in FGFR3 mRNA and a trend toward increased protein expression, similar to nonmuscle‐invasive disease.

[...]multiplexed analysis of CD3, CD4, CD8, CD25, FOXP3, and Ki67 would yield a more informative assessment of Treg and cytotoxic T cell relationship in the context of CTLA-4 blockade. [...]the importance of the spatial distribution of immune cell infiltrates have been highlighted in a recent study, showing that the density of CD8+ T cell infiltrates in the melanoma invasive margin was the best full predictive parameter of clinical response to anti-PD-1 immunotherapy [6]. In doing so, immune profile changes within TDLNs have been shown to correlate with clinical outcome [13–15]. [...]in a recent study, multispectral imaging of CD3, CD8, FOXP3, CD163, and PD-L1 was used to analyze the tumor microenvironment as a predictor of the successful generation and expansion of autologous tumor-reactive tumor infiltrating lymphocytes (TIL) in melanoma patients. Limitations of the approach Because multiplexed analyses on tissue are not common, there is risk that a lack of biological information could result from a multiplexed tissue biomarker imaging of 6 targets. [...]the results may not correlate with clinical status or outcome. [...]this approach could be rendered insufficient.

Background To date, there have been no reports characterizing the genome-wide somatic DNA chromosomal copy-number alteration landscape in metastatic urothelial carcinoma. We sought to characterize the DNA copy-number profile in a cohort of metastatic samples and compare them to a cohort of primary urothelial carcinoma samples in order to identify changes that are associated with progression from primary to metastatic disease. Methods Using molecular inversion probe array analysis we compared genome-wide chromosomal copy-number alterations between 30 metastatic and 29 primary UC samples. Whole transcriptome RNA-Seq analysis was also performed in primary and matched metastatic samples which was available for 9 patients. Results Based on a focused analysis of 32 genes in which alterations may be clinically actionable, there were significantly more amplifications/deletions in metastases (8.6% vs 4.5%, p < 0.001). In particular, there was a higher frequency of E2F3 amplification in metastases (30% vs 7%, p = 0.046). Paired primary and metastatic tissue was available for 11 patients and 3 of these had amplifications of potential clinical relevance in metastases that were not in the primary tumor including ERBB2 , CDK4, CCND1 , E2F3, and AKT1 . The transcriptional activity of these amplifications was supported by RNA expression data. Conclusions The discordance in alterations between primary and metastatic tissue may be of clinical relevance in the era of genomically directed precision cancer medicine.

The culmination of over a century’s work to understand the role of the immune system in tumor control has led to the recent advances in cancer immunotherapies that have resulted in durable clinical responses in patients with a variety of malignancies. Cancer immunotherapies are rapidly changing traditional treatment paradigms and expanding the therapeutic landscape for cancer patients. However, despite the current success of these therapies, not all patients respond to immunotherapy and even those that do often experience toxicities. Thus, there is a growing need to identify predictive and prognostic biomarkers that enhance our understanding of the mechanisms underlying the complex interactions between the immune system and cancer. Therefore, the Society for Immunotherapy of Cancer (SITC) reconvened an Immune Biomarkers Task Force to review state of the art technologies, identify current hurdlers, and make recommendations for the field. As a product of this task force, Working Group 2 (WG2), consisting of international experts from academia and industry, assembled to identify and discuss promising technologies for biomarker discovery and validation. Thus, this WG2 consensus paper will focus on the current status of emerging biomarkers for immune checkpoint blockade therapy and discuss novel technologies as well as high dimensional data analysis platforms that will be pivotal for future biomarker research. In addition, this paper will include a brief overview of the current challenges with recommendations for future biomarker discovery.

We evaluated primary tumors from two cohorts, Spain (N = 111) and Greece (N = 102), for patients who were treated with platinum‐based chemotherapy. Patients were tested for HER2 status (IHC score of 3+ or FISH ratio of ≥2.2) by immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), DNA copy number, mRNA expression, and mutation status in patients with metastatic urothelial carcinoma (UC), and its impact on survival. ERBB2 mutation was determined by hotspot sequencing. mRNA expression was assessed using NanoString counting. Association of overall survival (OS) and HER2 status was assessed by a Cox regression model. NIH‐3T3 cells containing HER2 V777L were assessed for growth, invasion, and HER2 kinase activation. In all, 22% of Spanish and 4% of Greek cohorts had 3+ HER2 staining by IHC. FISH amplification was identified in 20% of Spanish and 4% of Greek cohorts. Kappa coefficient between FISH and IHC was 0.47. HER2 status was not associated with OS in univariate (Spanish P = 0.34; Greek P = 0.11) or multivariate (Spanish P = 0.49; Greek P = 0.12) analysis. HER2‐positive tumors expressed higher levels of HER2 mRNA than HER2‐negative tumors (P < 0.001). HER2 mutations (V777L and L755S) were identified in two (2%) patients. In vitro analysis of V777L results in transformation of NIH‐3T3 cells, leading to increased growth, invasion on soft agar, and HER2 kinase constitutive activation. In summary, HER2 overexpression or amplification in the primary tumor did not predict OS in patients with metastatic UC. HER2 positivity rates can differ between different populations. Further trials in genomically screened patients are needed to assess HER2‐targeted therapies in UC. The association between HER2 status and overall survival (OS) in UC remains unclear. HER2 positivity may not only be a biomarker for more aggressive disease but also a potential therapeutic target. We report that HER2 overexpression or amplification in the primary tumor did not predict OS in patients with metastatic UC. Further trials in genomically screened patients are needed to assess HER2‐targeted therapies in UC.