PSMA heterogeneity and DNA repair defects in prostate cancer.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 5002-5002 ◽  
Author(s):  
Alec Paschalis ◽  
Beshara Sheehan ◽  
Ruth Riisnaes ◽  
Daniel Nava Rodrigues ◽  
Bora Gurel ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Genomic Analysis ◽  
Predictive Biomarkers ◽  
Parp Inhibition ◽  
Gleason Grade ◽  
Castration Resistant Prostate Cancer ◽  
Damage Repair ◽  
Promising Target ◽  
Molecular Aberrations ◽  
Next Generation Sequencing Ngs

5002 Background: Prostate-specific membrane antigen (PSMA) is a promising target for theranostics in metastatic castration resistant prostate cancer (mCRPC). Methods: Membranous PSMA (mPSMA) expression was immunohistochemically evaluated in castration sensitive (CSPC) (n = 38) and mCRPC (n = 60) tissue biopsies, and associations with molecular aberrations (next-generation sequencing; NGS) and clinical outcome were determined. Results: mPSMA expression was significantly higher (p = 0.005) in mCRPC biopsies (median H-score [interquartile range]; 55.0 [2.8-117.5]) compared to CSPC biopsies (17.5 [0.0-60.0]). Furthermore, patients with higher mPSMA expression ( > median H-score) at diagnosis had higher Gleason Grade (p = 0.04) and shorter OS (p = 0.006). Critically, 42% (16/38) of CSPC biopsies and 27% (16/60) of mCRPC biopsies were completely negative for mPSMA expression. In addition, CSPC and mCRPC biopsies expressing mPSMA demonstrated marked intra-tumor heterogeneity in expression levels, commonly exhibiting areas without detectable PSMA (CSPC – 100%; mCRPC – 84%), while heterogeneous mPSMA expression between metastases from the same patient was also observed. Subsequent genomic analysis showed that mCRPC patients with deleterious DNA damage repair (DDR) aberrations have higher (p = 0.016) mPSMA expression (87.5 [25.0-247.5]) than those without these (20 [0.3-98.8]). Furthermore, 9 of the 11 patients (82%) responding to PARP inhibition had a mPSMA H-Score above the median. The association between mPSMA expression and DDR aberrations was validated in an independent cohort with known DDR aberrations. Tumors with DDR aberrations had significantly higher mPSMA (ATM 212.5 [136.3-300] p = 0.005; BRCA2 300 [165-300] p = < 0.001) than unselected mCRPC biopsies (55.0 [2.75-117.5]). Finally, analyses of 122 mCRPC biopsy transcriptomes confirmed a negative correlation between PSMA and BRCA2 mRNA expression (p = 1.5x10-5). Conclusions: mPSMA expression in CSPC and mCRPC exhibits marked intra- and inter-patient heterogeneity, limiting the clinical utility of PSMA-targeted theranostics. We show for the first time that DDR gene aberrations associate with high mPSMA expression and may serve as predictive biomarkers for PSMA-targeted therapies.

scholarly journals Future therapeutic strategies for metastatic prostate cancer

2019 ◽  
Vol 9 (6-7) ◽  
pp. 117-130 ◽  
Author(s):  
Minke Smits ◽  
Winald Gerritsen ◽  
Niven Mehra
Keyword(s):  
Prostate Cancer ◽  
Metastatic Prostate Cancer ◽  
Predictive Biomarkers ◽  
Parp Inhibition ◽  
Oncological Patient ◽  
Damage Repair ◽  
Repair Deficiency ◽  
Disease Stabilization ◽  
Combination Regimens

Abstract During the last decade several new therapies have been investigated and approved for metastatic prostate cancer that greatly impacts patients’ quality of life and outcome. Nevertheless, optimal sequencing algorithms are still lacking, as are combinatory strategies that deliver long-term disease stabilization. Precision medicine, utilizing molecular profiles from tissue biopsies, will help us deliver optimal patient care by identifying patients that may benefit from targeted- and immunotherapy, and help guide treatment decisions by use of predictive biomarkers. Here, we present an overview of predictive biomarkers in prostate cancer, including mismatch repair and DNA damage repair deficiency, and promising novel targeted- and immunotherapies regimens, such as PSMA-radioligand therapy, PARP inhibition and PD-1/PD-L1 and CTLA‑4 checkpoint therapy. We anticipate that these agents in monotherapy and in combination regimens will alter uro-oncological patient management within the next ten years.

scholarly journals Harbingers of Aggressive Prostate Cancer: Precision Oncology Case Studies

2021 ◽  
Author(s):  
Joanna Cyrta ◽  
Davide Prandi ◽  
Arshi Arora ◽  
Daniel H. Hovelson ◽  
Andrea Sboner ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Phylogenetic Reconstruction ◽  
Genomic Analysis ◽  
Routine Practice ◽  
Molecular Heterogeneity ◽  
Precision Oncology ◽  
Gleason Grade ◽  
Metastatic Progression ◽  
Castration Resistant Prostate Cancer ◽  
Pathology Review

Primary prostate cancer (PCa) can show marked molecular heterogeneity. However, systematic analyses comparing primary PCa and matched metastases in individual patients are lacking. We aimed to address the molecular aspects of metastatic progression while accounting for heterogeneity of primary PCa. In this pilot study, we collected 12 radical prostatectomy (RP) specimens from men who subsequently developed metastatic castration-resistant prostate cancer (mCRPC). We used histomorphology (Gleason grade, focus size, stage) and immunohistochemistry (IHC) (ERG and p53) to identify independent tumors and/or distinct subclones of primary PCa. We then compared molecular profiles of these primary PCa areas to matched metastatic samples using whole exome sequencing (WES) and amplicon-based DNA and RNA sequencing. Based on combined pathology and molecular analysis, seven (58%) RP specimens harbored monoclonal and topographically continuous disease, albeit with some degree of intra-tumor heterogeneity; four (33%) specimens showed true multifocal disease; and one displayed monoclonal disease with discontinuous topography. Early (truncal) events in primary PCa included SPOP p.F133V (one patient), BRAF p.K601E (one patient), and TMPRSS2:ETS rearrangements (nine patients). Activating AR alterations were seen in eight (67%) mCRPC patients, but not in matched primary PCa. Hotspot TP53 mutations, found in metastases from three patients, were readily present in matched primary disease. Alterations in genes encoding epigenetic modifiers were observed in several patients (either shared between primary foci and metastases or in metastatic samples only). WES-based phylogenetic reconstruction and/or clonality scores were consistent with the index focus designated by pathology review in six out of nine (67%) cases. The three instances of discordance pertained to monoclonal, topographically continuous tumors, which would have been considered as unique disease in routine practice. Overall, our results emphasize pathologic and molecular heterogeneity of primary PCa, and suggest that comprehensive IHC-assisted pathology review and genomic analysis are highly concordant in nominating the ″index″ primary PCa area.

scholarly journals Impact of DNA damage repair defects and aggressive variant features on response to carboplatin‐based chemotherapy in metastatic castration‐resistant prostate cancer

2020 ◽  
Vol 148 (2) ◽  
pp. 385-395
Author(s):  
Peter H. J. Slootbeek ◽  
Marleen L. Duizer ◽  
Maarten J. Doelen ◽  
Iris S. H. Kloots ◽  
Malou C. P. Kuppen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Dna Damage Repair ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Damage Repair ◽  
Aggressive Variant

Genomic analysis of circulating tumor DNA in 3,334 patients with advanced prostate cancer to identify targetable BRCA alterations and AR resistance mechanisms.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 25-25
Author(s):  
Hanna Tukachinsky ◽  
Russell Madison ◽  
Jon Chung ◽  
Lucas Dennis ◽  
Bernard Fendler ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Advanced Prostate Cancer ◽  
Acquired Resistance ◽  
Genomic Analysis ◽  
Circulating Tumor Dna ◽  
Resistance Mechanisms ◽  
Cancer Tissue ◽  
Castration Resistant Prostate Cancer ◽  
High Level ◽  
Tumor Dna

25 Background: Comprehensive genomic profiling (CGP) by next-generation sequencing (NGS) of circulating tumor DNA (ctDNA) from plasma provides a minimally invasive method to identify targetable genomic alterations (GAs) and resistance mechanisms in patients with metastatic castration-resistant prostate cancer (mCRPC). The circulating tumor fraction in patients with mCRPC and the clinical validity of GAs detected in plasma remain unknown. We evaluated the landscape of GAs using ctDNA-based CGP and assessed concordance with tissue-based CGP. Methods: Plasma from 3,334 patients with advanced prostate cancer (including 1,674 mCRPC screening samples from the TRITON2/3 trials and 1,660 samples from routine clinical CGP) was analyzed using hybrid-capture-based gene panel NGS assays. Results were compared with CGP of 2,006 metastatic prostate cancer tissue biopsies. Concordance was evaluated in 837 patients with both tissue (archival or contemporaneous) and plasma NGS results. Results: 3,127 patients [94%] had detectable ctDNA. BRCA1/2 were mutated in 295 patients [8.8%]. In concordance analysis, 72/837 [8.6%] patients had BRCA1/2 mutations detected in tissue, 67 [93%] of whom were also identified by ctDNA, and 20 patients were identified using ctDNA but not tissue [23% of all patients identified using ctDNA]. ctDNA detected subclonal BRCA1/2 reversions in 10 of 1,660 [0.6%] routine clinical CGP samples. AR alterations, including amplifications and hotspot mutations, which were detected in 940/2,213 patients [42%]. Rare AR compound mutations, rearrangements, and novel in-frame deletions were identified. Altered pathways included PI3K/AKT/mTOR [14%], WNT/β-catenin [17%], and RAS/RAF/MEK [5%]. Microsatellite instability was detected in 31/2,213 patients [1.4%]. Conclusions: In the largest study of mCRPC plasma samples conducted to date, CGP of ctDNA recapitulated the genomic landscape detected in tissue biopsies, with a high level of agreement in detection of BRCA1/2 alterations. It also identified patients who may have gained somatic BRCA1/2 alterations since archival tissue was collected. ctDNA detected more acquired resistance GAs than tissue, including novel AR-activating variants. The large percentage of patients with rich genomic signal from ctDNA, and the sensitive, specific detection of BRCA1/2 alterations position liquid biopsy as a compelling clinical complement to tissue CGP for patients with mCRPC.

Anaplastic features (AnaF) and DNA-damage repair pathway (DDR) mutations in metastatic castration-resistant prostate cancer (mCRPC).

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 92-92
Author(s):  
Vincent Chau ◽  
Ravi Amrit Madan ◽  
Marijo Bilusic ◽  
Lisa M. Cordes ◽  
Jennifer L. Marte ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Bone Metastases ◽  
Mutational Analysis ◽  
Short Interval ◽  
Elevated Serum ◽  
High Volume ◽  
Small Cell ◽  
Castration Resistant Prostate Cancer ◽  
Damage Repair ◽  
Serum Cea

92 Background: Anaplastic prostate cancer displays features of small-cell carcinoma, a type of neuroendocrine tumor. Treatments for anaplastic prostate cancer are based on small cell lung cancer regimens. Both AnaF and mutations in DDR pathways, including BRCA2 confer an aggressive phenotype. For patients (pts) with certain DDR mutations, olaparib (O) was recently FDA approved, and an ongoing study is evaluating whether the addition of durvalumab (D) confers additional benefit in mCRPC (NCT02484404). We evaluate a potential preliminary relationship between DDR mutations, treatment with D and O, and AnaF. Methods: This is a phase II study of O plus D in pts with mCRPC with disease that is amenable to biopsy. On-study core biopsies undergo mutational analysis. Prior treatment with enzalutamide (enza) and/or abiraterone (abi) is required. D is given at 1500 mg iv q28 days + O 300 mg tablets po q12 hours. The primary endpoint is PFS. Pts were categorized into those with and without AnaF as defined by Aparicio et al. (2013). AnaF include small-cell histology; exclusively visceral metastases; predominantly lytic bone metastases; bulky lymphadenopathy (≥5 cm) or high-grade (Gleason ≥8) mass in prostate/pelvis; low PSA (≤10 ng/mL) at initial presentation with high volume (≥20) bone metastases; neuroendocrine markers in histology or serum plus elevated LDH, malignant hypercalcemia, or elevated serum CEA; or short interval (≤6 months) to androgen-independent progression. Results: Of 55 pts accrued, 24 had prior abi and enza; 19 pts had prior taxane. Common adverse events include anemia, fatigue, and nausea. Also, 11 pts (20.0%) displayed clear AnaF (Table) and 43 pts lacked AnaF, including 8 (14.5%) with partial AnaF that did not meet the full criteria, 4 (7.3%) who likely did not have AnaF due to difficulty in quantifying disease burden, 29 (52.7%) who did not have AnaF, and 2 (3.6%) had unknown status. Four pts (36.4%) with clear AnaF had DDR aberrations, including 3 (27.3%) with BRCA2, 1 (9.1%) with both BRCA2 and CHEK2, and 1 (9.1%) with ATM. Conclusions: Pts with mCRPC with DDR mutations can also have AnaF. This preliminary data demonstrates that pts with anaplastic prostate cancer and pts with DDR mutations are two distinct populations with some degree of overlap. O+D is well-tolerated, and future studies should focus on finding optimal treatments for pts with AnaF without and without DDR mutations. Clinical trial information: NCT02484404. [Table: see text]

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