• Activation of Akt characterizes estrogen receptor positive human breast cancers which respond to anthracyclines 

      Yndestad, Synnøve; Austreid, Eilin; Svanberg, Ida; Knappskog, Stian; Lønning, Per Eystein; Eikesdal, Hans Petter (Peer reviewed; Journal article, 2017-04-17)
      Anthracyclines are key components of human breast cancer chemotherapy. Here, we explored the role of Akt signaling in anthracycline resistance. The antitumor activity of doxorubicin and Akt inhibitor A-443654 alone or ...
    • Adjuvant treatment: the contribution of expression microarrays 

      Lønning, Per Eystein; Chrisanthar, Ranjan; Staalesen, Vidar; Knappskog, Stian; Lillehaug, Johan (Peer reviewed; Journal article, 2007-12-20)
    • Alterations of the retinoblastoma gene in metastatic breast cancer 

      Berge, Elisabet Ognedal; Knappskog, Stian; Lillehaug, Johan; Lønning, Per Eystein (Peer reviewed; Journal article, 2011-01-21)
      Germline mutations affecting the retinoblastoma gene (RB1) predispose to inherited retinoblastomas but also other malignancies, including breast cancer. While somatic RB1 mutations have been detected in different malignancies, ...
    • APOBEC3A/B deletion polymorphism and endometrial cancer risk 

      Sofiyeva, Nigar; Krakstad, Camilla; Halle, Mari Kyllesø; O'Mara, Tracy A.; Romundstad, Pål Richard; Hveem, Kristian; Vatten, Lars Johan; Lønning, Per Eystein; Gansmo, Liv Beathe; Knappskog, Stian (Journal article; Peer reviewed, 2022)
      Background A common 30 kb deletion affecting the APOBEC3A and APOBEC3B genes has been linked to increased APOBEC activity and APOBEC-related mutational signatures in human cancers. The role of this deletion as a cancer ...
    • Assessment of tumor suppressor promoter methylation in healthy individuals 

      Poduval, Deepak; Berge, Elisabet Ognedal; Sichmanovà, Zuzana; Valen, Eivind; Iversen, Gjertrud Titlestad; Minsaas, Laura; Lønning, Per Eystein; Knappskog, Stian (Journal article; Peer reviewed, 2020-08)
      Background The number of tumor suppressor genes for which germline mutations have been linked to cancer risk is steadily increasing. However, while recent reports have linked constitutional normal tissue promoter methylation ...
    • Associations between the MDM2 promoter P1 polymorphism del1518 (rs3730485) and incidence of cancer of the breast, lung, colon and prostate 

      Gansmo, Liv Beathe; Vatten, Lars Johan; Romundstad, Pål Richard; Hveem, Kristian; Ryan, Bríd M.; Harris, Curtis C.; Knappskog, Stian; Lønning, Per Eystein (Peer reviewed; Journal article, 2016-04-12)
      The MDM2 promoter region contains several polymorphisms, some of which have been associated with MDM2 expression, cancer risk and age at cancer onset. del1518 (rs3730485) is an indel polymorphism residing in the MDM2 ...
    • C/EBPB-dependent adaptation to palmitic acid promotes tumor formation in hormone receptor negative breast cancer 

      Liu, Xiaozheng; Rulina, Anastasiia; Choi, Man Hung; Pedersen, Line; Lepland, Johanna; Takle, Sina Thorsen; Madeleine, Noëlly; Peters, Stacey D'mello; Wogsland, Cara Ellen; Grøndal, Sturla Magnus; Lorens, James Bradley; Goodarzi, Hani; Lønning, Per Eystein; Knappskog, Stian; Molven, Anders; Halberg, Nils Henrik (Journal article; Peer reviewed, 2022)
      Epidemiological studies have established a positive association between obesity and the incidence of postmenopausal breast cancer. Moreover, it is known that obesity promotes stem cell-like properties of breast cancer ...
    • 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 ...
    • Clonal evolution in primary breast cancers under sequential epirubicin and docetaxel monotherapy 

      Venizelos, Andreas; Engebrethsen, Christina; Deng, Wei; Geisler, Jürgen; Geisler, Stephanie; Iversen, Gjertrud Titlestad; Aas, Turid; Aase, Hildegunn Siv; Seyedzadeh, Manouchehr; Steinskog, Eli Sihn Samdal; Myklebost, Ola; Nakken, Sigve; Vodák, Daniel; Hovig, Eivind; Meza, Leonardo Zepeda; Lønning, Per Eystein; Knappskog, Stian; Eikesdal, Hans Petter (Journal article; Peer reviewed, 2022)
      Background Subclonal evolution during primary breast cancer treatment is largely unexplored. We aimed to assess the dynamic changes in subclonal composition of treatment-naïve breast cancers during neoadjuvant ...
    • 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 ...
    • Constitutional BRCA1 methylation and risk of incident triple-negative breast cancer and high-grade serous ovarian cancer 

      Lønning, Per Eystein; Nikolaienko, Oleksii; Pan, Kathy; Kurian, Allison W.; Eikesdal, Hans Petter; Pettinger, Mary; Anderson, Garnet L.; Prentice, Ross L.; Chlebowski, Rowan T.; Knappskog, Stian (Journal article; Peer reviewed, 2022)
      Importance About 25% of all triple-negative breast cancers (TNBCs) and 10% to 20% of high-grade serous ovarian cancers (HGSOCs) harbor BRCA1 promoter methylation. While constitutional BRCA1 promoter methylation has been ...
    • DNA methylation changes in response to neoadjuvant chemotherapy are associated with breast cancer survival 

      Pedersen, Christine Aaserød; Cao, Maria Dung; Fleischer, Thomas; Rye, Morten Beck; Knappskog, Stian; Eikesdal, Hans Petter; Lønning, Per Eystein; Tost, Jörg; Kristensen, Vessela N.; Tessem, May-Britt; Giskeødegård, Guro F.; Bathen, Tone Frost (Journal article; Peer reviewed, 2022)
      Background: Locally advanced breast cancer is a heterogeneous disease with respect to response to neoadjuvant chemotherapy (NACT) and survival. It is currently not possible to accurately predict who will benefit from the ...
    • DNA methylation profiling in doxorubicin treated primary locally advanced breast tumours identifies novel genes associated with survival and treatment response 

      Dejeux, Emelyne; Rønneberg, Jo A.; Solvang, Hiroko Kato; Bukholm, Ida Rashida Khan; Geisler, Stephanie; Aas, Turid; Gut, Ivo G.; Børresen-Dale, Anne-Lise; Lønning, Per Eystein; Kristensen, Vessela N.; Tost, Jörg (Peer reviewed; Journal article, 2010-03-25)
      Background: Breast cancer is the most frequent cancer in women and consists of a heterogeneous collection of diseases with distinct histopathological, genetic and epigenetic characteristics. In this study, we aimed to ...
    • Effect of the MDM2 promoter polymorphisms SNP309T>G and SNP285G>C on the risk of ovarian cancer in BRCA1 mutation carriers 

      Bjørnslett, Merete; Knappskog, Stian; Lønning, Per Eystein; Dørum, Anne (Peer reviewed; Journal article, 2012-10-05)
      Background: While BRCA mutation carriers possess a 20-40% lifetime risk of developing ovarian cancer, knowledge about genetic modifying factors influencing the phenotypic expression remains obscure. We explored the ...
    • Effects of SNP variants in the 17β-HSD2 and 17β-HSD7 genes and 17β-HSD7 copy number on gene transcript and estradiol levels in breast cancer tissue 

      Straume, Anne Hege; Knappskog, Stian; Lønning, Per Eystein (Peer reviewed; Journal article, 2014-02-18)
      Breast cancers reveal elevated E2 levels compared to plasma and normal breast tissue. Previously, we reported intra-tumour E2 to be negatively correlated to transcription levels of 17β-HSD2 but positively correlated to ...
    • Epithelial to mesenchymal transition (EMT) is associated with attenuation of succinate dehydrogenase (SDH) in breast cancer through reduced expression of SDHC 

      Røsland, Gro Vatne; Dyrstad, Sissel Elisabeth; Tusubira, Deusdedit; Helwa, Reham; Tan, Tuan Zea; Lotsberg, Maria Lie; Pettersen, Ina Katrine Nitschke; Berg, Anna; Kindt, Charlotte; Hoel, Fredrik; Jacobsen, Kristine; Arason, Ari Jon; Engelsen, Agnete; Ditzel, Henrik J.; Lønning, Per Eystein; Krakstad, Camilla; Thiery, Jean Paul; Lorens, James; Knappskog, Stian; Tronstad, Karl Johan (Peer reviewed; Journal article, 2019-06-01)
      Background: Epithelial to mesenchymal transition (EMT) is a well-characterized process of cell plasticity that may involve metabolic rewiring. In cancer, EMT is associated with malignant progression, tumor heterogeneity, ...
    • Estradiol measurement in translational studies of breast cancer 

      Lønning, Per Eystein (Peer reviewed; Journal article, 2015-07)
      Plasma estrogen measurement with use of radioimmunoassays has been instrumental in the development of aromatase inhibitors for endocrine therapy of postmenopausal breast cancer. However, due to low plasma estrogen ...
    • Expression of full-length p53 and its isoform Δp53 in breast carcinomas in relation to mutation status and clinical parameters 

      Baumbusch, Lars O.; Myhre, Simen; Langerød, Anita; Bergamaschi, Anna; Geisler, Stephanie; Lønning, Per Eystein; Deppert, Wolfgang; Dornreiter, Irene; Børresen-Dale, Anne-Lise (Molecular Cancer 5(47), Peer reviewed; Journal article, 2006-10-20)
      Background: The tumor suppressor gene p53 (TP53) controls numerous signaling pathways and is frequently mutated in human cancers. Novel p53 isoforms suggest alternative splicing as a regulatory feature of p53 activity. ...
    • High PTEN gene expression is a negative prognostic marker in human primary breast cancers with preserved p53 function 

      Yndestad, Synnøve; Austreid, Eilin; Knappskog, Stian; Chrisanthar, Ranjan; Lilleng, Peer Kåre; Lønning, Per Eystein; Eikesdal, Hans Petter (Peer reviewed; Journal article, 2017)
      Purpose: PTEN is an important tumor suppressor in breast cancer. Here, we examined the prognostic and predictive value of PTEN and PTEN pseudogene (PTENP1) gene expression in patients with locally advanced breast cancer ...
    • Identification and characterization of retinoblastoma gene mutations disturbing apoptosis in human breast cancers 

      Berge, Elisabet Ognedal; Knappskog, Stian; Geisler, Stephanie; Staalesen, Vidar; Pacal, Marec; Børresen-Dale, Anne-Lise; Puntervoll, Pål; Lillehaug, Johan; Lønning, Per Eystein (Peer reviewed; Journal article, 2010-07-01)
      Background The tumor suppressor pRb plays a key role regulating cell cycle arrest, and disturbances in the RB1 gene have been reported in different cancer forms. However, the literature reports contradictory findings with ...