title: Association of positive EBAG9 immunoreactivity with unfavorable prognosis in breast cancer patients treated with tamoxifen.
abstract: BACKGROUND
  Breast cancer is primarily a hormone-dependent tumor that is regulated by the status of the estrogen and progesterone receptors. We previously identified EBAG9 as an estrogen-responsive gene in MCF-7 human breast carcinoma cells. Upregulation of EBAG9 expression has been observed in several malignant tumors such as advanced breast cancers, indicating that EBAG9 might contribute to tumor progression.
  
  
  METHODS
  In the present study, we generated a monoclonal antibody against EBAG9, and then performed immunohistochemical analysis of EBAG9 expression in specimens obtained from breast cancer patients treated with tamoxifen as an adjuvant therapy.
  
  
  RESULTS
  EBAG9 immunoreactivity was detected in the cytoplasm of breast cancer cells and was significantly elevated in breast cancer samples from patients who relapsed during or after adjuvant tamoxifen treatment. Positive EBAG9 immunoreactivity was significantly correlated with poor patient prognosis.
  
  
  CONCLUSIONS
  These results suggest that EBAG9 expression in tumor regions is associated with an unfavorable prognosis in breast cancer patients treated with tamoxifen.
authors.affiliation: Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Ijichi
authors.forename: Takashi
authors.initials: T
authors.lastname: Shigekawa
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ikeda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Kuniko
authors.initials: K
authors.lastname: Horie-Inoue
authors.forename: Chikako
authors.initials: C
authors.lastname: Shimizu
authors.forename: Shigehira
authors.initials: S
authors.lastname: Saji
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Aogi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Osaki
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Saeki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inoue
mesh_terms: D000951:Antigens, Neoplasm / Q000378:metabolism*; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000601:surgery; D016022:Case-Control Studies; D003131:Combined Modality Therapy; D003593:Cytoplasm / Q000378:metabolism; D019008:Drug Resistance, Neoplasm; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008408:Mastectomy; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000378:metabolism / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate; D013629:Tamoxifen / Q000627:therapeutic use*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D018931:Antineoplastic Agents, Hormonal; C120762:EBAG9 protein, human; D013629:Tamoxifen
keywords: EBAG9; Endocrine therapy; Immunohistochemistry; Prognostic factor; Tamoxifen resistance