Expression of six-transmembrane epithelial antigen of the prostate in prostate cancer and its correlation with prostate specific antigen / 中华泌尿外科杂志

ABSTRACT

Objective To investigate the expression of six-transmembrane epithelial antigen of the prostate (STEAP) in prostate cancer and its relationship with prostate specific antigen (PSA).Methods A retrospective analysis was performed of 65 consecutive patients verified for prostate canc-er by prostate biopsy or post-operational pathological examination.The clinical stage was classified ac-cording to TNM system and the pathological grade was classified according to Gleason score.STEAP expression in 65 prostate cancer samples (T1 9,T2 14,T3 17,T4 25;high differentiation 37,moder-ate differentiation 12 and low differentiation 16) was studied by using STEAP monoclonal antibody (Santa Cruz Biotech,USA) and SP immunohistochemical staining.Positive staining gray values were introduced to describe the intensity of STEAP expression.STEAP expression level was analyzed with respect to stage,grade,serum total PSA and free/total PSA (f/t PSA) ratio respectively.Results The serum total PSA concentration and f/t PSA ratio in all cases was (27.65±8.34) ng/ml and 0.15～0.04 respectively.STEAP was positively stained in 63 patients (T1 7,T2 14,T3 17,T4 25; high differentiation 37,moderate differentiation 11 and low differentiation 15).The mean STEAP-positive staining gray values in stage T1,T2,T3 and T4 of prostate cancer were 26.8%,45.6%,62.3% and 76.5%,respectively and in high,moderate and low differentiation group were 71.2%,52.8%,and 34.4% respectively.The positive staining gray values of STEAP expression was posi-tively correlated to the clinical stage of cancer and negatively correlated to the Gleason score and the ratio of f/t PSA (P<0.01,respectively).There was no significant relationship between STEAP ex-pression and serum total PSA concentration (P>0.05).Conclusion STEAP expression may act as one of new markers to the invasion degree and pathological grade of prostate cancer.