• Associations between tamoxifen, estrogens, and FSH serum levels during steady state tamoxifen treatment of postmenopausal women with breast cancer 

      Gjerde, Jennifer; Geisler, Jürgen; Lundgren, Steinar; Ekse, Dagfinn; Varhaug, Jan Erik; Mellgren, Gunnar; Steen, Vidar Martin; Lien, Ernst Asbjørn (Peer reviewed; Journal article, 2010-06-21)
      Background The cytochrome P450 (CYP) enzymes 2C19, 2D6, and 3A5 are responsible for converting the selective estrogen receptor modulator (SERM), tamoxifen to its active metabolites 4-hydroxy-tamoxifen (4OHtam) and ...
    • CHEK2 Mutations Affecting Kinase Activity Together With Mutations in TP53 Indicate a Functional Pathway Associated with Resistance to Epirubicin in Primary Breast Cancer 

      Chrisanthar, Ranjan; Knappskog, Stian; Løkkevik, Erik; Anker, Gun Birgitta; Østenstad, Bjørn; Lundgren, Steinar; Berge, Elisabet Ognedal; Risberg, Terje; Mjaaland, Ingvil; Mæhle, Lovise; Engebretsen, Lars Fredrik; Lillehaug, Johan; Lønning, Per Eystein (Peer reviewed; Journal article, 2008-08-26)
      Background: Chemoresistance is the main obstacle to cure in most malignant diseases. Anthracyclines are among the main drugs used for breast cancer therapy and in many other malignant conditions. Single parameter analysis ...
    • Concomitant inactivation of the p53- and pRB- functional pathways predicts resistance to DNA damaging drugs in breast cancer in vivo 

      Knappskog, Stian; Berge, Elisabet Ognedal; Chrisanthar, Ranjan; Geisler, Stephanie; Staalesen, Vidar; Leirvaag, Beryl; Yndestad, Synnøve; de Faveri, Elise Norheim; Karlsen, Bård Ove; Wedge, David C.; Akslen, Lars A.; Lilleng, Peer Kåre; Løkkevik, Erik; Lundgren, Steinar; Østenstad, Bjørn; Risberg, Terje; Mjaaland, Ingvil; Aas, Turid; Lønning, Per Eystein (Peer reviewed; Journal article, 2015-10)
      Chemoresistance is the main obstacle to cancer cure. Contrasting studies focusing on single gene mutations, we hypothesize chemoresistance to be due to inactivation of key pathways affecting cellular mechanisms such as ...
    • Low expression levels of ATM may substitute for CHEK2 / TP53 mutations predicting resistance towards anthracycline and mitomycin chemotherapy in breast cancer 

      Knappskog, Stian; Chrisanthar, Ranjan; Løkkevik, Erik; Anker, Gun Birgitta; Østenstad, Bjørn; Lundgren, Steinar; Risberg, Terje; Mjaaland, Ingvil; Leirvaag, Beryl; Miletic, Hrvoje; Lønning, Per Eystein (Peer reviewed; Journal article, 2012-03-15)
      Introduction: Mutations affecting p53 or its upstream activator Chk2 are associated with resistance to DNAdamaging chemotherapy in breast cancer. ATM (Ataxia Telangiectasia Mutated protein) is the key activator of p53 and ...
    • Olaparib monotherapy as primary treatment in unselected triple negative breast cancer 

      Eikesdal, Hans Petter; Yndestad, Synnøve; Elzawahry, Asmaa; Llop-Guevara, Alba; Gilje, Bjørnar; Blix, Egil Støre; Espelid, Helge; Lundgren, Steinar; Geisler, Jürgen; Vagstad, Geirfinn; Venizelos, Andreas; Minsaas, Laura; Leirvaag, Beryl; Gudlaugsson, Einar; Vintermyr, Olav Karsten; Aase, Hildegunn Siv; Aas, Turid; Balmaña, Judith; Serra, Violeta; Janssen, Emiel; Knappskog, Stian; Lønning, Per Eystein (Journal article; Peer reviewed, 2020)
      Background The antitumor efficacy of PARP inhibitors (PARPi) for breast cancer patients harboring germline BRCA1/2 (gBRCA1/2) mutations is well established. While PARPi monotherapy was ineffective in patients with metastatic ...
    • Persistence of disseminated tumor cells after neoadjuvant treatment for locally advanced breast cancer predicts poor survival 

      Mathiesen, Randi Margit Ruud; Borgen, Elin; Renolen, Anne; Løkkevik, Erik; Nesland, Jahn M.; Anker, Gun; Østenstad, Bjørn; Lundgren, Steinar; Risberg, Terje; Mjaaland, Ingvil; Kvalheim, Gunnar; Lønning, Per Eystein; Naume, Bjørn (Peer reviewed; Journal article, 2012-08-14)
      Introduction: Presence of disseminated tumor cells (DTCs) in bone marrow (BM) and circulating tumor cells (CTC) in peripheral blood (PB) predicts reduced survival in early breast cancer. The aim of this study was to determine ...
    • Predictive and Prognostic Impact of TP53 Mutations and MDM2 Promoter Genotype in Primary Breast Cancer Patients Treated with Epirubicin or Paclitaxel 

      Chrisanthar, Ranjan; Knappskog, Stian; Løkkevik, Erik; Anker, Gun Birgitta; Østenstad, Bjørn; Lundgren, Steinar; Risberg, Terje; Mjaaland, Ingvil; Skjønsberg, Gudbrand; Aas, Turid; Schlichting, Ellen; Fjösne, Hans E.; Nysted, Arne; Lillehaug, Johan; Lønning, Per Eystein (Peer reviewed; Journal article, 2011-04-27)
      Background: TP53 mutations have been associated with resistance to anthracyclines but not to taxanes in breast cancer patients. The MDM2 promoter single nucleotide polymorphism (SNP) T309G increases MDM2 activity and may ...
    • Prenatal BRCA1 epimutations contribute significantly to triple-negative breast cancer development 

      Nikolaienko, Oleksii; Eikesdal, Hans Petter; Berge, Elisabet Ognedal; Gilje, Bjørnar; Lundgren, Steinar; Blix, Egil Støre; Espelid, Helge; Geisler, Jürgen; Geisler, Stephanie; Janssen, Emiel; Yndestad, Synnøve; Minsaas, Laura; Leirvaag, Beryl; Lillestøl, Reidun Kristine; Knappskog, Stian; Lønning, Per Eystein (Journal article; Peer reviewed, 2023)
      Background Normal cell BRCA1 epimutations have been associated with increased risk of triple-negative breast cancer (TNBC). However, the fraction of TNBCs that may have BRCA1 epimutations as their underlying cause is ...
    • Prognostic value of metabolic response in breast cancer patients receiving neoadjuvant chemotherapy 

      Cao, Maria Dung; Giskeødegård, Guro F.; Bathen, Tone Frost; Sitter, Beathe; Bofin, Anna; Lønning, Per Eystein; Lundgren, Steinar; Gribbestad, Ingrid S. (Peer reviewed; Journal article, 2012-01-25)
      Background: Today’s clinical diagnostic tools are insufficient for giving accurate prognosis to breast cancer patients. The aim of our study was to examine the tumor metabolic changes in patients with locally advanced ...
    • Semi-automatic segmentation from intrinsically-registered 18F-FDG-PET/MRI for treatment response assessment in a breast cancer cohort: comparison to manual DCE-MRI 

      Andreassen, Maren Marie Sjaastad; Goa, Pål Erik; Sjøbakk, Torill Eidhammer; Hedayati, Roja; Eikesdal, Hans Petter; Deng, Callie; Østlie, Agnes; Lundgren, Steinar; Bathen, Tone Frost; Jerome, Neil Peter (Peer reviewed; Journal article, 2019-09-27)
      Objectives: To investigate the reliability of simultaneous positron emission tomography and magnetic resonance imaging (PET/MRI)-derived biomarkers using semi-automated Gaussian mixture model (GMM) segmentation on PET ...