title: Clinicopathological analyses of triple negative breast cancer using surveillance data from the Registration Committee of the Japanese Breast Cancer Society.
abstract: BACKGROUND
  Triple negative (TN) breast cancer is defined as a subtype that is negative for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2). To clarify the characteristics of TN breast cancer, surveillance data of the Registration Committee of the Japanese Breast Cancer Society were analyzed.
  
  
  METHODS
  Of 14,748 cases registered in 2004, 11,705 (79.4%) were examined for ER, PgR, and HER2. Of these, the most prevalent (53.8%) was a hormone-responsive subtype with ER positive/PgR positive/HER2 negative, followed by TN subtype (15.5%).
  
  
  RESULTS
  The proportion of postmenopausal patients was relatively high in the TN subtype. This cancer was diagnosed at a slightly advanced stage and with more cases positive for lymph node metastases than other subtypes. Morphologically, the TN subtype was more frequently classified as solid-tubular carcinoma. Mucinous, tubular, or secretary carcinomas were frequently found in the hormone receptor positive/HER2 negative subtype, while squamous cell carcinoma, spindle cell carcinoma, and metaplastic carcinoma with bone/cartilage metaplasia were very frequently found in the TN group. Apocrine carcinoma was also found very frequently in the TN group. Selection of chemotherapy was not based on receptor subtypes, but was determined by the degree of tumor progression.
  
  
  CONCLUSIONS
  Although TN types are similar to basal-like breast tumor, as determined by gene profiling, their diagnosis needs verification by determination of the level of epidermal growth factor receptor or cytokeratin 5/6 expression. TN type should be examined further for immunohistochemical features and analyzed for prognostic details in this cohort.
authors.affiliation: Member of the Research Group, Japanese Breast Cancer Society, Tokyo, Japan. hiwase@kumamoto-u.ac.jp
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Iwase
authors.forename: Junichi
authors.initials: J
authors.lastname: Kurebayashi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tsuda
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Ohta
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kurosumi
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwase
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology; D002293:Adenocarcinoma, Scirrhous / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D007564:Japan; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012042:Registries; D012955:Societies, Medical / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone