title: [Prevalence of breast cancer sub-types by immunohistochemistry in patients in the Regional General Hospital 72, Instituto Mexicano del Seguro Social].
abstract: BACKGROUND
  Breast cancer mortality has increased in women 25 years and over, and since 2006 it has surpassed cervical cancer. Breast cancer is a heterogeneous disease, with several clinical and histological presentations that require a thorough study of all clinical and pathological parameters, including immunohistochemistry to classify it into subtypes, have a better prognosis, provide individualised treatment, increase survival, and reduce mortality.
  
  
  OBJECTIVE
  To evaluate the prevalence of sub-types of breast cancer and the association with the clinical and histopathological features of the tumour.
  
  
  METHODS
  An observational, retrospective, cross-sectional and analytical study conducted on 1380 patients with a diagnosis of breast cancer have been classified by immunohistochemistry into four subtypes: luminal A, triple negative, luminal B and HER2. An analysis was performed on the association with age, risk factors, and the clinical and histopathological features of the tumour.
  
  
  RESULTS
  The mean age of the patients was 53.3 ± 11.4. The frequency was luminal A (65%), triple negative (14%), luminal B (12%), and HER2 (9%). The most frequent characteristics were the 50 to 59 age range, late menopause, the right side, upper external quadrant, stage II, metastatic lymph nodes, and mastectomy.
  
  
  CONCLUSIONS
  The most frequent sub-type was luminal A, and together with the luminal B are those which have better prognosis compared with the triple negative and HER2.
authors.affiliation: División de Atención Ginecobstétrica y Perinatal, Dirección de Prestaciones Médicas Instituto Mexicano del Seguro Social, México D.F., México. Electronic address: gabriel.perezr@imss.gob.mx.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Pérez-Rodríguez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000145:classification* / Q000453:epidemiology / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006769:Hospitals, General; D006801:Humans; D007150:Immunohistochemistry; D008800:Mexico; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies
keywords: Breast cancer; Cáncer de mama; Immunohistochemistry; Inmunohistoquímica; Molecular subtypes; Subtipos moleculares