Publications by authors named "Flohr P"

Article Synopsis
  • - PARP inhibitors show promise in treating castration-resistant prostate cancer (CRPC) with homologous recombination repair (HRR) defects, but the reasons behind resistance are not completely understood.
  • - A study from the TOPARP-B trial found that 79% of BRCA2/PALB2-mutated tumors exhibited reversion mutations at the end of treatment, with many related to POLQ-mediated DNA repair mechanisms.
  • - In cases of BRCA2 homozygous deletions, rare subclones lacking the BRCA2 deletion are selected for after PARP inhibitor treatment, indicating the necessity for restored HRR function in developing resistance.
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  • The study investigates the effectiveness of the AKT inhibitor capivasertib when combined with enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) who did not respond well to prior treatments with abiraterone acetate and docetaxel.
  • Conducted as a double-blind, randomized phase 2 trial with 100 men, the primary focus was on the composite response rate, which showed no significant improvement with the combination treatment compared to placebo.
  • Analysis revealed that patients with PTEN loss had poorer overall survival regardless of treatment, with common side effects including diarrhea and fatigue, indicating that while the combination was tolerable, it did not enhance treatment outcomes.
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Malignant transformation is characterised by aberrant phospholipid metabolism of cancers, associated with the upregulation of choline kinase alpha (CHKα). Due to the metabolic instability of choline radiotracers and the increasing use of late-imaging protocols, we developed a more stable choline radiotracer, [F]fluoromethyl-[1,2-H]choline ([F]D4-FCH). [F]D4-FCH has improved protection against choline oxidase, the key choline catabolic enzyme, via a H/D isotope effect, together with fluorine substitution.

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Inflammation is a hallmark of cancer. In patients with cancer, peripheral blood myeloid expansion, indicated by a high neutrophil-to-lymphocyte ratio, associates with shorter survival and treatment resistance across malignancies and therapeutic modalities. Whether myeloid inflammation drives progression of prostate cancer in humans remain unclear.

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Prostate cancer is the most common cancer in men and it is estimated that over 350,000 men worldwide die of prostate cancer every year. There remains an unmet clinical need to improve how clinically significant prostate cancer is diagnosed and develop new treatments for advanced disease. Aberrant glycosylation is a hallmark of cancer implicated in tumour growth, metastasis, and immune evasion.

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Article Synopsis
  • - Researchers found that HER3, a protein often overexpressed in aggressive prostate cancer, is linked to faster progression to castration resistance and lower survival rates.
  • - The study identified that NRG1, a ligand for HER3, is primarily produced by certain immune cells in the tumor environment, and its presence promotes cancer cell growth.
  • - Targeting HER3 with specific therapies, like the antibody-drug conjugate U3-1402, shows promise in fighting HER3-positive prostate cancer, suggesting the need for further clinical trials.
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The microbiota comprises the microorganisms that live in close contact with the host, with mutual benefit for both counterparts. The contribution of the gut microbiota to the emergence of castration-resistant prostate cancer (CRPC) has not yet been addressed. We found that androgen deprivation in mice and humans promotes the expansion of defined commensal microbiota that contributes to the onset of castration resistance in mice.

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Article Synopsis
  • Better blood tests are needed for metastatic castration-resistant prostate cancer (mCRPC) to guide treatment decisions, and low-pass whole-genome sequencing (lpWGS) of circulating tumor DNA (ctDNA) shows promise in providing insights into mCRPC behavior.
  • The study examined plasma lpWGS data from 188 mCRPC patients undergoing two phase 3 clinical trials, with an aim to assess its prognostic value and its ability to correlate with treatment response.
  • Findings suggest that plasma tumor fraction is a strong predictor of overall survival and is more informative than existing biomarkers, while genomic instability indicated by large-scale transition scores was linked to previous treatments but not to others like taxane or radiation therapy.*
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Circulating tumor cell (CTC) enumeration and changes following treatment have been demonstrated to be superior to PSA response in determining mCRPC outcome in patients receiving AR signaling inhibitors but not taxanes. We carried out a pooled analysis of two prospective studies in mCRPC patients treated with docetaxel. CTCs were measured at baseline and 3-6 weeks post treatment initiation.

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Article Synopsis
  • About 50% of patients with metastatic castration-resistant prostate cancer (mCRPC) have issues with the PI3K/AKT/mTOR pathway due to lost PTEN, and combining treatments that target the androgen receptor and AKT could help them.
  • In a study, mCRPC patients who didn’t respond to previous treatments received different doses of capivasertib along with enzalutamide to evaluate safety and effectiveness.
  • The recommended dose of capivasertib was found to be 400 mg twice daily, with manageable side effects and some patients showing significant positive responses, particularly those with specific genetic characteristics.
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Background: Metastatic castration-resistant prostate cancer is enriched in DNA damage response (DDR) gene aberrations. The TOPARP-B trial aims to prospectively validate the association between DDR gene aberrations and response to olaparib in metastatic castration-resistant prostate cancer.

Methods: In this open-label, investigator-initiated, randomised phase 2 trial following a selection (or pick-the-winner) design, we recruited participants from 17 UK hospitals.

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Purpose: Onalespib is a potent, fragment-derived second-generation HSP90 inhibitor with preclinical activity in castration-resistant prostate cancer (CPRC) models. This phase I/II trial evaluated onalespib in combination with abiraterone acetate (AA) and either prednisone or prednisolone (P) in men with CRPC progressing on AA/P.

Patients And Methods: Patients with progressing CRPC were randomly assigned to receive 1 of 2 regimens of onalespib combined with AA/P.

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Background: Detection of androgen receptor splice variant-7 (AR-V7) mRNA in circulating tumour cells (CTCs) is associated with worse outcome in metastatic castration-resistant prostate cancer (mCRPC). However, studies rarely report comparisons with CTC counts and biopsy AR-V7 protein expression.

Objective: To determine the reproducibility of AdnaTest CTC AR-V7 testing, and associations with clinical characteristics, CellSearch CTC counts, tumour biopsy AR-V7 protein expression and overall survival (OS).

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The presence of high expressing epithelial cell adhesion molecule (EpCAM) circulating tumor cells (CTC) enumerated by CellSearch in blood of cancer patients is strongly associated with poor prognosis. This raises the question about the presence and relation with clinical outcome of low EpCAM expressing CTC (EpCAM CTC). In the EU-FP7 CTC-Trap program, we investigated the presence of EpCAM and EpCAM CTC using CellSearch, followed by microfiltration of the EpCAM CTC depleted blood.

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To explore morphological features of circulating tumor cells (CTCs) and tumor-derived extracellular vesicles (tdEVs), we developed a protocol for scanning electron microscopy (SEM) of CTCs and tdEVs. CTCs and tdEVs were isolated by immunomagnetic enrichment based on their Epithelial Cell Adhesion Molecule (EpCAM) expression or by physical separation through 5 μm microsieves from 7.5 mL of blood from Castration-Resistant Prostate Cancer (CRPC) patients.

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Circulating tumor cells (CTCs) have clinical relevance, but their study has been limited by their low frequency. We evaluated liquid biopsies by apheresis to increase CTC yield from patients suffering from metastatic prostate cancer, allow precise gene copy-number calls, and study disease heterogeneity. Apheresis was well tolerated and allowed the separation of large numbers of CTCs; the average CTC yield from 7.

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Frequently, the number of circulating tumor cells (CTC) isolated in 7.5 mL of blood is too small to reliably determine tumor heterogeneity and to be representative as a "liquid biopsy". In the EU FP7 program CTCTrap, we aimed to validate and optimize the recently introduced Diagnostic LeukApheresis (DLA) to screen liters of blood.

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Background: The development of treatment response and surrogate biomarkers for advanced prostate cancer care is an unmet clinical need. Patients with baseline circulating tumour cell (BLCTCs) counts <5/7.5 mL represent a good prognosis subgroup but are non-evaluable for response assessment (decrease in CTCs).

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Article Synopsis
  • The study investigates the role of Circulating Tumor Cells (CTCs) and tumor-derived Extracellular Vesicles (tdEVs) in predicting overall survival for patients with Castration-Resistant Prostate Cancer (CRPC).
  • It involved isolating and counting CTCs and tdEVs in 129 CRPC patients, using established biomarkers to differentiate between favorable and unfavorable prognoses based on overall survival data.
  • Results showed that both CTCs and tdEVs, along with other plasma markers, were higher in CRPC patients compared to healthy individuals, with tdEVs providing comparable prognostic information to CTC counts in assessing patient outcomes.
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  • * The study analyzed blood samples from 571 mCRPC patients in two clinical trials, examining the relationship between cfDNA levels and patient outcomes such as prostate-specific antigen (PSA) response, radiological progression-free survival (rPFS), and overall survival (OS).
  • * Results indicated that higher baseline cfDNA concentrations correlated with poorer rPFS and OS, making cfDNA an independent prognostic factor, while declines in cfDNA levels during treatment were associated with positive PSA responses; however, the study faced some limitations.
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Chromosomal instability and associated chromosomal aberrations are hallmarks of cancer and play a critical role in disease progression and development of resistance to drugs. Single-cell genome analysis has gained interest in latest years as a source of biomarkers for targeted-therapy selection and drug resistance, and several methods have been developed to amplify the genomic DNA and to produce libraries suitable for Whole Genome Sequencing (WGS). However, most protocols require several enzymatic and cleanup steps, thus increasing the complexity and length of protocols, while robustness and speed are key factors for clinical applications.

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Biomarkers for more precise patient care are needed in metastatic prostate cancer. We have reported a phase II trial (TOPARP-A) of the PARP inhibitor olaparib in metastatic prostate cancer, demonstrating antitumor activity associating with homologous recombination DNA repair defects. We now report targeted and whole-exome sequencing of serial circulating cell-free DNA (cfDNA) samples collected during this trial.

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Background: Deletion of the chromatin remodeler chromodomain helicase DNA-binding protein 1 (CHD1) is a common genomic alteration found in human prostate cancers (PCas). CHD1 loss represents a distinct PCa subtype characterized by SPOP mutation and higher genomic instability. However, the role of CHD1 in PCa development in vivo and its clinical utility remain unclear.

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Direct analysis of circulating tumor cells (CTCs) can inform on molecular mechanisms underlying systemic spread. Here we investigated promoter methylation of three genes regulating epithelial-to-mesenchymal transition (EMT), a key mechanism enabling epithelial tumor cells to disseminate and metastasize. For this, we developed a single-cell protocol based on agarose-embedded bisulfite treatment, which allows investigating DNA methylation of multiple loci via a multiplex PCR (multiplexed-scAEBS).

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Molecular and epidemiological differences have been described between TMPRSS2:ERG fusion-positive and fusion-negative prostate cancer (PrCa). Assuming two molecularly distinct subtypes, we have examined 27 common PrCa risk variants, previously identified in genome-wide association studies, for subtype specific associations in a total of 1221 TMPRSS2:ERG phenotyped PrCa cases. In meta-analyses of a discovery set of 552 cases with TMPRSS2:ERG data and 7650 unaffected men from five centers we have found support for the hypothesis that several common risk variants are associated with one particular subtype rather than with PrCa in general.

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