Loss of Wave1 gene defines a subtype of lethal prostate cancer

Genetic alterations involving TMPRSS2-ERG alterations and deletion of key tumor suppressor genes are associated with development and progression of prostate cancer (PCa). However, less defined are early events that may contribute to the development of high-risk metastatic prostate cancer. Bioinformatic analysis of existing tumor genomic data from PCa patients revealed that WAVE complex gene alterations are associated with a greater likelihood of prostate cancer recurrence. Further analysis of primary vs. castration resistant prostate cancer indicate that disruption of WAVE complex gene expression, and particularly WAVE1 gene (WASF1) loss, is also associated with castration resistance, where WASF1 is frequently co-deleted with PTEN and resists androgen deprivation therapy (ADT). Hence, we propose that WASF1 status defines a subtype of ADT-resistant patients. Better understanding of the effects of WAVE pathway disruption will lead to development of better diagnostic and treatment modalities

The Role of Immunohistochemical Analysis as a Tool for the Diagnosis, Prognostic Evaluation and Treatment of Prostate Cancer: A Systematic Review of the Literature

Background: Prostate cancer (PCa) is a heterogeneous disease that lends itself toward numerous therapeutic options depending on its risk stratification. One of the greatest challenges in PCa urologic practice is to select patients who should be referred for biopsy and, for those patients who are diagnosed with cancer, to differentiate between patients with indolent disease from those with an unfavorable prognosis and, to determine ideal patient management and avoid unnecessary interventions. Accordingly, there is a growing body of literature reporting immunohistochemical studies with the objective of determining a prostate cancer prognosis. Among the most frequent biomarkers studied are Ki-67, p53, PTEN, MYC, and ERG. Based on these findings, we systematically reviewed articles that assessed the role of these main prognostic markers in prostate cancer.Methods: Consistent with PRISMA guidelines, we performed a systematic literature search throughout the Web of Science and PubMed Medline databases. We considered all types of studies evaluating the role of Ki-67, p53, PTEN, MYC, and ERG immunohistochemical analysis in prostate cancer until July 2017.Results: We identified 361 articles, 44 of which were summarized in this review. Diagnostically, no single immunohistochemical marker was able to define a tumor as benign or malignant. Prognostically, Ki-67, p53, and MYC were related to the tumor grade given by Gleason score and to the tumor stage (higher levels related to higher tumor grade). Furthermore, Ki-67 was also related to higher PSA levels, shorter disease-free intervals and shorter tumor-specific survival; the latter was also related to p53. The loss of PTEN protein expression showed a higher association with biochemical recurrence and with a worse prognosis, beyond that predicted by the Gleason score and tumor stage. ERG staining also showed a strong association with biochemical recurrence.Conclusion: There are several studies relating immunohistochemical markers with clinical-laboratorial outcomes in prostate cancer, the most frequent being Ki-67, p53, ERG, PTEN, and MYC. However, none of these markers have been validated by literary consensus to be routinely applied in medical practice

Battling the two-headed dragon of prostate cancer targeted therapy

Neoadjuvant intense androgen deprivation therapy for high-risk localized prostate cancer is an emerging but unproven treatment paradigm that is hoped to delay or prevent disease recurrence. We found that a patient enrolled in a clinical trial harbored two completely independent prostate cancers that responded differently to this therapy

Reciprocal regulation of Abl kinase by Crk Y251 and Abi1 controls invasive phenotypes in glioblastoma

Crk is the prototypical member of a class of Src homology 2 (SH2) and Src homology 3 (SH3) domain-containing adaptor proteins that positively regulate cell motility via the activation of Rac1 and, in certain tumor types such as GBM, can promote cell invasion and metastasis by mechanisms that are not well understood. Here we demonstrate that Crk, via its phosphorylation at Tyr251, promotes invasive behavior of tumor cells, is a prominent feature in GBM, and correlating with aggressive glioma grade IV staging and overall poor survival outcomes. At the molecular level, Tyr251 phosphorylation of Crk is negatively regulated by Abi1, which competes for Crk binding to Abl and attenuates Abl transactivation. Together, these results show that Crk and Abi1 have reciprocal biological effects and act as a molecular rheostat to control Abl activation and cell invasion. Finally, these data suggest that Crk Tyr251 phosphorylation regulate invasive cell phenotypes and may serve as a biomarker for aggressive GBM

Quantitative and Qualitative Analysis of Blood-based Liquid Biopsies to Inform Clinical Decision-making in Prostate Cancer.

ContextGenomic stratification can impact prostate cancer (PC) care through diagnostic, prognostic, and predictive biomarkers that aid in clinical decision-making. The temporal and spatial genomic heterogeneity of PC together with the challenges of acquiring metastatic tissue biopsies hinder implementation of tissue-based molecular profiling in routine clinical practice. Blood-based liquid biopsies are an attractive, minimally invasive alternative.ObjectiveTo review the clinical value of blood-based liquid biopsy assays in PC and identify potential applications to accelerate the development of precision medicine.Evidence acquisitionA systematic review of PubMed/MEDLINE was performed to identify relevant literature on blood-based circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and extracellular vesicles (EVs) in PC.Evidence synthesisLiquid biopsy has emerged as a practical tool to profile tumor dynamics over time, elucidating features that evolve (genome, epigenome, transcriptome, and proteome) with tumor progression. Liquid biopsy tests encompass analysis of DNA, RNA, and proteins that can be detected in CTCs, ctDNA, or EVs. Blood-based liquid biopsies have demonstrated promise in the context of localized tumors (diagnostic signatures, risk stratification, and disease monitoring) and advanced disease (response/resistance biomarkers and prognostic markers).ConclusionsLiquid biopsies have value as a source of prognostic, predictive, and response biomarkers in PC. Most clinical applications have been developed in the advanced metastatic setting, where CTC and ctDNA yields are significantly higher. However, standardization of assays and analytical/clinical validation is necessary prior to clinical implementation.Patient summaryTraces of tumors can be isolated from blood samples from patients with prostate cancer either as whole cells or as DNA fragments. These traces provide information on tumor features. These minimally invasive tests can guide diagnosis and treatment selection

Abstract B049: Radiogenomic profiling of prostate tumors prior to external beam radiotherapy (EBRT) converges on a transcriptomic signature of TGF-beta activity driving tumor recurrence

Abstract Background: In patients who receive definitive therapy for locally advanced prostate cancer, biochemical recurrence is due to local recurrence and/or the presence of undetected metastatic disease at the time of initial diagnosis and treatment. Approximately 25-40% of patients who receive radiotherapy plus androgen deprivation therapy (ADT) with curative intent are expected to recur within 5-10 years. We hypothesized that applying multiparametric (mp) MRI, gene expression, and genomic analyses to prostate tumors prior to EBRT+ADT would identify biomarkers predictive of recurrence (NCT01834001). Methods: At baseline and 6 months after completion of radiotherapy, mpMRI was performed and lesions were manually contoured. MR/ultrasound-fusion biopsies acquired at baseline targeted to up to three distinct MR lesions per patient. 29 patients with intermediate and high risk localized prostate cancer treated with EBRT+ADT with sufficient baseline biopsy tissue were selected for this analysis (median follow-up: 91 months). Tumor tissues were macrodissected to obtain DNA and RNA from 60 distinct biopsy regions (1-4 per patient). DNA was used for generating whole-exome sequencing libraries (92.5 × median coverage); RNA was converted into cDNA and hybridized to Affymetrix Human Exon 1.0 microarrays. Secondary gene expression cohorts with clinical annotation were obtained from the University of Miami and Queen’s University Belfast. Gene expression signatures were processed using Ingenuity Pathway Analysis (IPA) and the Decipher GRID. Results: Five of the 29 patients experienced biochemical failure by the time of data analysis; four of these patients were identified to have distant metastases with no evidence of local recurrence at the time of biochemical failure. Baseline and posttreatment lesion volumes by MRI and posttreatment ADCmax (apparent diffusion coefficient) were positively associated with recurrence (p<0.05). The Decipher signature positively correlated with these three MR features. Comparison of gene expression using a linear mixed-effect model identified 1,120 differentially expressed transcripts. IPA nominated TGF-beta signaling as the topmost enriched upstream regulator (z=3.32). This result was validated in the Miami (z=2.54) and Belfast (z=3.67) cohorts. By network analysis, genes that independently tracked with the baseline and posttreatment volumes and posttreatment ADCmax MR features similarly converged to the TGF-beta pathway. Co-occurrence of biallelic TP53 alterations with 1- or 2-copy PTEN losses was observed exclusively in patients who recurred. Conclusions: Genomic, transcriptomic and radiomic analyses have nominated predictive biomarkers that identify the subset of patients with locally advanced prostate cancer destined to recur after definitive EBRT+ADT. Identification of molecular features predictive of failure suggests that aggressive pre-existing subclones harboring these alterations have metastatic potential. Emerging systemic therapies including TGF-beta ligand traps targeted to these tumors may improve overall outcomes. Citation Format: Adam G. Sowalsky, Anson T. Ku, Uma Shankavaram, Shana Y. Trostel, Houssein A. Sater, Stephanie A. Harmon, Nicole V. Carrabba, Yang Liu, Radka Stoyanova, Elai Davicioni, Alan Pollack, Baris Turkbey, Deborah E. Citrin. Radiogenomic profiling of prostate tumors prior to external beam radiotherapy (EBRT) converges on a transcriptomic signature of TGF-beta activity driving tumor recurrence [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B049