AIM:The study evaluated the immunohistochemistry expression of endothelin-1 (ET-1) by prostate cancer (PCa) in prostate biopsies as an extracapsular stage (pT3a) prognostic factor. MATERIAL AND METHOD:Sixty-eight radical prostatectomies (RP) were performed for clinically localised PCa (35 pT2 and 33 pT3a according to the 2002 pTNM classification). Age, digital rectal examination, initial PSA, biopsy Gleason score, positive biopsies ratio, specimen Gleason score, biopsy and RP specimen perineural neoplasic invasion, PCa DNA ploidy, PCa Ki-67 DNA image cytometry and biopsy and RP specimen ET-1 immunohistochemistry expression for both group were compared. Semi-quantitative ET-1 staining assessment was realised by the same pathologist. RESULTS:pT3a group initial PSA was higher (p=0.032). No statistically difference was noticed between pT2 and pT3a groups for positive biopsies ratio, biopsy perineural neoplastic invasion and biopsy DNA ploidy determination. Biopsy Gleason score > or =7 was predictive of a pT3a stage (p=0.03). Statistically higher intensity of ET-1 PCa expression was observed in biopsies and specimens in pT3a group than in pT2 group (p<0.001 and p=0.01). In multivariate analysis, biopsy ET-1 PCa expression was an independent risk factor of pT3a stage with specificity 79 %, sensibility 69 %, predictive positive value 77 % and negative positive value 72 %. Combined with initial PSA > or =7, values were respectively 100 %, 76.9 %, 100 % and 57.1 %. CONCLUSION:Endothelin-1 (ET-1) prostate cancer biopsy expression in our study was an independent prognostic factor of extracapsular stage (pT3a). Further studies will assess the relevance of ET-1 expression study in clinically localised PCa for active surveillance, curative treatment or targeted adjuvant therapy management.