title: PAR1 is selectively over expressed in high grade breast cancer patients: a cohort study.
abstract: BACKGROUND
  The protease-activated receptor (PAR1) expression is correlated with the degree of invasiveness in cell lines. Nevertheless it has never been directed involved in breast cancer patients progression. The aim of this study was to determine whether PAR1 expression could be used as predictor of metastases and mortality.
  
  
  METHODS
  In a cohort of patients with infiltrating ductal carcinoma studied longitudinally since 1996 and until 2007, PAR1 over-expression was assessed by immunoblotting, immunohistochemistry, and flow citometry. Chi-square and log rank tests were used to determine whether there was a statistical association between PAR1 overexpression and metastases, mortality, and survival. Multivariate analysis was performed including HER1, stage, ER and nodes status to evaluate PAR1 as an independent prognostic factor.
  
  
  RESULTS
  Follow up was 95 months (range: 2-130 months). We assayed PAR1 in a cohort of patients composed of 136 patients; we found PAR1 expression assayed by immunoblotting was selectively associated with high grade patients (50 cases of the study cohort; P = 0.001). Twenty-nine of 50 (58%) patients overexpressed PAR1, and 23 of these (46%) developed metastases. HER1, stage, ER and PAR1 overexpression were robustly correlated (Cox regression, P = 0.002, P = 0.024 and P = 0.002 respectively). Twenty-one of the 50 patients (42%) expressed both receptors (PAR1 and HER1 P = 0.0004). We also found a statistically significant correlation between PAR1 overexpression and increased mortality (P = 0.0001) and development of metastases (P = 0.0009).
  
  
  CONCLUSIONS
  Our data suggest PAR1 overexpression may be involved in the development of metastases in breast cancer patient and is associated with undifferentiated cellular progression of the tumor. Further studies are needed to understand PAR1 mechanism of action and in a near future assay its potential use as risk factor for metastasis development in high grade breast cancer patients.
authors.affiliation: Subdirección de Investigación Básica, Instituto Nacional de Cancerología, Mexico City, Mexico. normahernandez21@yahoo.com
authors.forename: Norma A
authors.initials: NA
authors.lastname: Hernández
authors.forename: Elma
authors.initials: E
authors.lastname: Correa
authors.forename: Esther P
authors.initials: EP
authors.lastname: Avila
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Vela
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Pérez
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000401:mortality / Q000473:pathology* / Q000556:secondary; D045744:Cell Line, Tumor; D015331:Cohort Studies; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D044463:Receptor, PAR-1 / Q000378:metabolism*; D012641:Selection, Genetic; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D044463:Receptor, PAR-1