title: Increased phosphorylation of Akt in triple-negative breast cancers.
abstract: Cells from breast cancers lacking hormone receptors (estrogen receptor [ER], progesterone receptor [PgR]) and human epidermal growth factor receptor (HER) 2 strongly express the cell proliferation marker Ki-67. However, the mechanisms of and stimulus signals involved in cell proliferation of this type of breast cancer are not well understood. The aim of the present study was to examine the characteristics of signal transduction in triple-negative (ER-, PgR-, and HER2-negative) breast cancers. For 44 tumor samples, western blotting analysis was conducted to examine the phosphorylation of HER2, external signal-regulated kinase (ERK)1 and -2 and Akt, and the immunohistochemical phenotypes of the samples with respect to ER and HER2 were also assessed. Phosphorylation of HER2 was detected in 4 of 15 immunohistochemically HER2-positive tumor samples (26.7%). ERK1/2 was more highly phosphorylated in triple-negative breast cancers. Phosphorylation of Akt kinase was significantly higher in triple-negative breast cancers. Triple-negative breast cancers are characterized by increased phosphorylation of Akt kinase. In the present study, we found for the first time that there is a population with a significantly activated Akt pathway in this type of breast cancer.
authors: Department of Pathology, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan. umemura@is.icc.u-tokai.ac.jp
authors: Shinobu
authors: S
authors: Umemura
authors: Sei
authors: S
authors: Yoshida
authors: Yoshikazu
authors: Y
authors: Ohta
authors: Kenichiro
authors: K
authors: Naito
authors: R Yoshiyuki
authors: RY
authors: Osamura
authors: Yutaka
authors: Y
authors: Tokuda
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D002278:Carcinoma in Situ / Q000473:pathology / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000032:analysis / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis
chemical_list: D051057:Proto-Oncogene Proteins c-akt; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human