Publications by authors named "Tjensvoll K"

Tumor-derived extracellular vesicles (EVs) are reported to contain nucleic acids, including DNA. Several studies have highlighted the potential of EV-derived DNA (evDNA) as a circulating biomarker, even demonstrating that evDNA can outperform cell-free DNA (cfDNA) in terms of sensitivity. Here, we evaluated EVs as a potential source of tumor-derived DNA in patients with advanced pancreatic cancer.

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Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with a need for better tools to guide treatment selection and follow-up. The aim of this prospective study was to investigate the prognostic value and treatment monitoring potential of longitudinal circulating tumour DNA (ctDNA) measurements in patients with advanced PDAC undergoing palliative chemotherapy. Using KRAS peptide nucleic acid clamp-PCR, we measured ctDNA levels in plasma samples obtained at baseline and every 4 weeks during chemotherapy from 81 patients with locally advanced and metastatic PDAC.

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Purpose: Circulating tumor DNA (ctDNA) has emerged as a promising tumor-specific biomarker in pancreatic cancer, but current evidence of the clinical potential of ctDNA is limited. In this study, we used comprehensive detection methodology to explore the utility of longitudinal ctDNA measurements in patients with advanced pancreatic cancer.

Experimental Design: A targeted eight-gene next-generation sequencing panel was used to detect point mutations and copy-number aberrations (CNA) in ctDNA from 324 pre-treatment and longitudinal plasma samples obtained from 56 patients with advanced pancreatic cancer.

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Background: Although pancreatic ductal adenocarcinoma (PDAC) rarely metastasizes to the skeleton, disseminated tumor cells have been detected in bone marrow samples from patients with this disease. The prognostic value of such findings is currently unclear. Thus, the current study aimed to clarify the prognostic information associated with disseminated tumor cell detection in samples from patients with PDAC.

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Article Synopsis
  • - Breast cancer remains the most common cancer among women globally, prompting the Prospective Breast Cancer Biobank (PBCB) study to collect blood and urine samples from patients for 11 years to search for new biomarkers that can help detect recurrences at the molecular level.
  • - The study involves 1,455 early-stage breast cancer patients providing samples every 6-12 months, and their data will be compared with responses from 200 cancer-free women for a comprehensive analysis of cancer biology and patient outcomes.
  • - The PBCB study has received ethical approvals, allowing for comprehensive research and sharing of findings to contribute to global understanding and improvements in breast cancer treatment.
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  • Circulating tumor DNA (ctDNA) analysis is gaining importance for diagnosing and monitoring cancer but is challenging due to low DNA levels and technical issues.
  • This study presents a new method called HYTEC-seq, which improves ctDNA detection using Ion Torrent sequencing by combining hybridization capture and molecular tagging.
  • HYTEC-seq has shown promising results, detecting mutations in plasma samples from advanced pancreatic cancer patients with high sensitivity (down to 0.1%) and specificity (>99.99%), identifying mutations in 57% of tested patients.
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Liquid biopsies have emerged as a potential new diagnostic tool, providing detailed information relevant for characterization and treatment of solid cancers. We here present an overview of current evidence supporting the clinical relevance of liquid biopsy assessments. We also discuss the implementation of liquid biopsies in clinical studies and their current and future clinical role, with a special reference to the Nordic healthcare systems.

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Background: Operable breast cancer patients may experience late recurrences because of reactivation of dormant tumor cells within the bone marrow (BM). Identification of patients who would benefit from extended therapy is therefore needed.

Methods: BM samples obtained pre- and post-surgery were previously analysed for presence of disseminated tumor cells (DTC) by a multimarker mRNA quantitative reverse-transcription PCR assay.

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Background: Reliable methods are needed to identify patients with early-stage cancer or high-grade precancerous lesions in the pancreas. Analysis of pancreatic juice to detect somatic mutations could represent one such approach. Here we investigated the concordance between mutations found in the primary tumor and pancreatic juice from the same patient.

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Background: It was recently demonstrated that the size of cell-free DNA (cfDNA) fragments that originates from tumor cells are shorter than cfDNA fragments that originates from non-malignant cells. We investigated whether cfDNA fragment size and cfDNA levels might have prognostic value in patients with advanced pancreatic cancer.

Methods: Blood samples were obtained from patients with advanced pancreatic cancer, before (n = 61) initiation of chemotherapy and after the first cycle of chemotherapy (n = 39).

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Background: Regional lymph node (LN) metastasis is a strong and well-established prognostic factor in colon cancer, and recent data suggest a prognostic value of detecting micrometastases and isolated tumor cells in regional LNs. The aim of the study was to investigate the clinical relevance of detecting sentinel lymph node (SLN) metastases in colon cancer patients by measuring the novel metastasis marker PHGR1 mRNA.

Methods: Using quantitative reverse-transcription polymerase chain reaction, we measured PHGR1 mRNA levels in SLNs and primary tumors from 206 patients surgically treated for stage I to III colon cancer and 52 normal LNs from patients undergoing surgery for benign colon diseases.

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Background: The primary function of the intestines is the absorption of water and nutrients. Although our knowledge about these processes on the cellular level is extensive, a number of important intracellular elements remain unknown. Here, we characterize the novel proline-, histidine-, glycine-rich 1 (PHGR1) mRNA and protein on the molecular level and propose a functional role of the PHGR1 protein in the intestinal and gastric epithelium.

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Article Synopsis
  • Blood contains circulating tumor cells (CTCs) and tumor-derived DNA (ctDNA), making it a valuable source for cancer liquid biopsies.
  • Methods for enhancing and detecting CTCs and ctDNA can support their clinical use, particularly for gastrointestinal cancers like colorectal, gastric, and pancreatic cancers.
  • Liquid biopsies can improve cancer management by minimizing invasive procedures, aiding in screening, treatment monitoring, and tumor genotyping.
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Background: Single-cell mRNA profiling of circulating tumour cells may contribute to a better understanding of the biology of these cells and their role in the metastatic process. In addition, such analyses may reveal new knowledge about the mechanisms underlying chemotherapy resistance and tumour progression in patients with cancer.

Methods: Single circulating tumour cells were isolated from patients with locally advanced or metastatic pancreatic cancer with immuno-magnetic depletion and immuno-fluorescence microscopy.

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  • Current CTC enrichment methods focus on the epithelial protein EpCAM, which may miss CTCs with non-epithelial characteristics due to epithelial-mesenchymal transition.
  • The new MINDEC strategy uses a multi-marker approach to deplete blood cells, showing an impressive 82% recovery rate of CTCs and effectively reducing residual white blood cell counts.
  • Clinical tests in metastatic pancreatic cancer patients revealed CTCs in 71% of blood samples, suggesting MINDEC's potential for broader clinical application pending larger trials.
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  • The study focused on KRAS mutations to assess the importance of circulating tumor DNA (ctDNA) in advanced pancreatic cancer patients undergoing chemotherapy.
  • Blood samples were collected from 14 patients before and during treatment, using a specialized PCR method to detect KRAS mutations as a marker for ctDNA.
  • The results indicated that higher pre-treatment ctDNA levels were linked to worse disease outcomes, suggesting ctDNA could help monitor treatment effectiveness and disease progression in pancreatic cancer.
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Background: The Norwegian Electronic Health Library (The Library) is a website for health personnel. Most of the content is also open to the public. Usage statistics have risen sharply in the years 2010-2013.

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Background: Disseminated tumor cells (DTCs) have potential to predict the effect of adjuvant treatment. The purpose of this study was to compare two methods, reverse transcription quantitative PCR (RT-qPCR) and immunocytochemisty (ICC), for detecting breast cancer DTCs in bone marrow (BM) from early breast cancer patients.

Methods: We investigated a subset (n = 313) of BM samples obtained from 271 early breast cancer patients in the "Secondary Adjuvant Taxotere Treatment" (SATT)-trial.

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The poor prognosis of pancreatic cancer patients is associated with the frequent and early dissemination of the disease, as well as late detection due to unspecific and late symptoms from the primary tumor. Pancreatic cancers frequently spread to the liver, lung and skeletal system, suggesting that pancreatic tumor cells must be able to intravasate and travel through the circulation to distant organs. Circulating tumor cells (CTCs) are tumor cells that have acquired the ability to enter the circulatory system; this cell population is ultimately responsible for the development of metastases in distant organs.

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Purpose: To investigate the prognostic value of occult metastases detected by quantitative measurements of candidate biomarkers in sentinel lymph nodes (SLNs) from patients curatively resected for colon cancer.

Methods: Resection specimens from consecutive patients undergoing surgery for localized colon cancer were subjected to ex vivo SLN mapping. SLNs were examined for the presence of metastases by routine hematoxylin-erythrosin-safranin staining and by cytokeratin 20 (CK20) and mucin 2 (MUC2) mRNA quantification.

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Article Synopsis
  • The study aimed to assess the impact of disseminated tumor cells (DTCs) in the bone marrow of non-metastatic breast cancer patients before and after surgery.
  • Analysis was conducted on bone marrow samples from 154 patients collected post-surgery, revealing that 15% had persistent DTCs, which correlated with a significantly higher rate of systemic relapse.
  • The presence of DTCs after surgery was identified as an independent predictor of poor survival, with patients showing DTCs before and after surgery facing the highest risk of systemic recurrence and reduced survival rates.
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  • The study aimed to find miRNA biomarkers that could help detect breast cancer early and identify minimal residual disease.
  • Substantial increases in the levels of five specific miRNAs were found in breast tumors compared to healthy samples.
  • However, further testing of these miRNAs and additional candidates did not support their potential as reliable biomarkers for breast cancer detection.
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Point mutations in the K-ras gene have been shown to confer resistance against epidermal growth factor receptor-directed therapy of metastatic colorectal cancer. Accordingly, K-ras mutation testing has become mandatory in hospitals offering such treatment. We compared the performance and reagent costs of 2 sensitive methods for detection of K-ras mutations: a peptide nucleic acid (PNA) clamp polymerase chain reaction (PCR) assay and a commercially available amplification refractory mutation system/Scorpion (ARMS/S) PCR assay.

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Purpose: K-ras mutations predict resistance against epidermal growth factor receptor (EGFR)-directed therapy of metastatic colorectal cancer (CRC). The purpose of this study was to analyze the distribution of K-ras mutations in primary tumors and corresponding sentinel lymph nodes (SLNs) from colon cancer patients.

Methods: Tumor biopsies and SLNs from 158 patients with non-metastatic colon cancer were analyzed for K-ras mutations in codons 12 and 13 by a sensitive and quantitative peptide nucleic acid clamp PCR assay.

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