title: Translational studies within the TAMRAD randomized GINECO trial: evidence for mTORC1 activation marker as a predictive factor for everolimus efficacy in advanced breast cancer.
abstract: BACKGROUND
  Everolimus is an agent frequently associated with specific toxicities. Predictive markers of efficacy are needed to help define which patients could benefit from it. The goal of this exploratory study was to identify potential predictive biomarkers in the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) activation pathway using primary tumor samples collected during the phase II tamoxifen plus everolimus (TAMRAD) trial.
  
  
  METHODS
  Tumor tissues were collected retrospectively from the TAMRAD trial. Immunohistochemistry was carried out using specific antibodies directed toward proteins that result in mTORC1 activation [canonical phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mTOR or alternative pathways]. DNA was extracted from the tumor tissue; mutation screening in the PIK3CA gene (exons 9 and 20) and the KRAS gene (exons 2 and 3) was first carried out using Sanger direct sequencing, and then completed by next-generation sequencing for PIK3CA. An exploratory analysis of everolimus efficacy in terms of a time-to-progression (TTP) increase was carried out in each biomarker subgroup (high versus low expression referring to the median percentage of marked cells).
  
  
  RESULTS
  A total of 55 primary tumor samples from the TAMRAD trial—25 from the tamoxifen-alone group and 30 from the tamoxifen/everolimus group—were evaluated for biomarkers. The subgroups most likely to have an improvement in TTP with tamoxifen/everolimus therapy, compared with tamoxifen alone, were patients with high p4EBP1, low 4EBP1, low liver kinase B1, low pAkt, and low PI3K. Among the 45 samples screened for mutation status, nine samples (20%; 95% CI 9.6-34.6) had a PIK3CA mutation. KRAS mutation was observed in one patient.
  
  
  CONCLUSIONS
  A positive correlation between late effectors of mTORC1 activation, a positive correlation between Akt-independent mTORC1 activation, and an inverse correlation between canonical PI3K/Akt/mTOR pathway and everolimus efficacy were observed in this exploratory analysis. However, these correlations need to be validated in larger studies before applying the findings to routine clinical practice.
authors.affiliation: Department of Anatomopathology, Centre Léon Bérard, Lyon.
authors.forename: I
authors.initials: I
authors.lastname: Treilleux
authors.affiliation: Oncology Department, Gustave Roussy, Villejuif.
authors.forename: M
authors.initials: M
authors.lastname: Arnedos
authors.affiliation: Biostatistics and Therapeutic Evaluation Unit.
authors.forename: C
authors.initials: C
authors.lastname: Cropet
authors.affiliation: Genomic Platform-Translational Research Laboratory, Centre Léon Bérard, Lyon.
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Medical Oncology Department, Centre Antoine Lacassagne, Nice.
authors.forename: J-M
authors.initials: JM
authors.lastname: Ferrero
authors.affiliation: Medical Oncology Department, Centre Paul Papin, Angers.
authors.forename: S
authors.initials: S
authors.lastname: Abadie-Lacourtoisie
authors.affiliation: Oncology Department, Centre François Baclesse, Caen.
authors.forename: C
authors.initials: C
authors.lastname: Levy
authors.affiliation: Hematology and Oncology Department, Clinique de Valdegour, Nimes.
authors.forename: E
authors.initials: E
authors.lastname: Legouffe
authors.affiliation: Oncology Department, Centre Catherine de Sienne, Nantes.
authors.forename: A
authors.initials: A
authors.lastname: Lortholary
authors.affiliation: Oncology Department, Université Paris Descartes, AP-HP, Hôpitaux Universitaires Paris Centre, Site Hôtel-Dieu, Paris.
authors.forename: E
authors.initials: E
authors.lastname: Pujade-Lauraine
authors.affiliation: Hematology and Oncology Department, Centre Hospitalier Départemental Les Oudairies, La Roche-Sur-Yon.
authors.forename: A-V
authors.initials: AV
authors.lastname: Bourcier
authors.affiliation: Department of Medicine, Institut Jean Godinot, Reims.
authors.forename: J-C
authors.initials: JC
authors.lastname: Eymard
authors.affiliation: Oncology Department, Centre d'Oncologie de Gentilly, Nancy.
authors.forename: D
authors.initials: D
authors.lastname: Spaeth
authors.affiliation: 2B North Department, Department of Medical Oncology and Cancer Research Center of Lyon, Centre Léon Bérard, Lyon, France. Electronic address: thomas.bachelot@lyon.unicancer.fr.
authors.forename: T
authors.initials: T
authors.lastname: Bachelot
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality; D018797:Cell Cycle Proteins; D058534:Class I Phosphatidylinositol 3-Kinases; D000068338:Everolimus; D005260:Female; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1; D008875:Middle Aged; D046912:Multiprotein Complexes / Q000235:genetics*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D017422:Sequence Analysis, DNA; D020123:Sirolimus / Q000031:analogs & derivatives* / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D013629:Tamoxifen / Q000627:therapeutic use; D018631:ras Proteins / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D058534:Class I Phosphatidylinositol 3-Kinases; D000068338:Everolimus; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D016283:Proto-Oncogene Proteins p21(ras); D020123:Sirolimus; D058570:TOR Serine-Threonine Kinases; D013629:Tamoxifen; D018631:ras Proteins; C087000:EIF4EBP1 protein, human; C117307:KRAS protein, human; C546842:MTOR protein, human; C484760:PIK3CA protein, human
keywords: biomarkers; breast cancer; everolimus; mTORC1; tamoxifen