title: Expression of prostate apoptosis response (Par-4) is associated with progesterone receptor in breast cancer.
abstract: BACKGROUND
  The prostate apoptosis response (Par-4) gene encodes a proapoptotic protein that selectively induces apoptosis in cancer cells after diverse apoptotic stimuli. Par-4 expression and its association with other biomarkers have not been reported in breast cancer. The purpose of this study was to determine Par-4 expression in breast cancer samples and its association with other biomarkers and clinical factors (T-stage, age, nodal status).
  
  
  METHODS
  Paraffin-embedded section samples of breast cancer were evaluated by immunohistochemical analysis to determine Par-4, estrogen receptor (ER), progesterone receptor (PgR), c-erbB2, Ki67, p53 and bcl-2 expression. The correlation between Par-4 and the other biomarkers and clinical factors was determined by multivariate analysis.
  
  
  RESULTS
  Thirty five percent (n=21) of samples were PAR-4 positive and 64.4% (n=38) were negative. The hormonal status was 64% ER positive (n=38), 35% ER-negative (n=21) and 40.7% PgR positive (n=24), 59.3% PgR negative (n=35). The majority (90%) of the samples presented clear cytoplasmic localization and a small portion (10%) was cytoplasmic and nuclear. Univariate analysis indicates that the Par-4 expression has a significant inverse association (p=0.04) only with expression of PgR and not with the other variables analyzed. Normal breast tissue analyzed was negative for Par-4 immunostaining.
  
  
  CONCLUSIONS
  Our results suggest that, in breast cancer, Par-4 plays a similar tumor suppressor gene role as reported in endometrial carcinoma.
authors.affiliation: Departamento de Inmunología y Virología, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, México.
authors.forename: Pablo
authors.initials: P
authors.lastname: Zapata-Benavides
authors.forename: José L
authors.initials: JL
authors.lastname: Méndez-Vázquez
authors.forename: Talina R
authors.initials: TR
authors.lastname: González-Rocha
authors.forename: Diana E
authors.initials: DE
authors.lastname: Zamora-Avila
authors.forename: Moises A
authors.initials: MA
authors.lastname: Franco-Molina
authors.forename: Raúl
authors.initials: R
authors.lastname: Garza-Garza
authors.forename: Cristina
authors.initials: C
authors.lastname: Rodriguez-Padilla
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D051017:Apoptosis Regulatory Proteins; D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C101296:prostate apoptosis response-4 protein