STEAP1 protein overexpression is an independent marker for biochemical recurrence in prostate carcinoma

Aims To investigate the prognostic value of expression levels of the genes STEAP 1 and STEAP 2, and of STEAP 1 protein, in prostate carcinomas ( PC a). Methods and results STEAP 1 and STEAP 2 transcript levels were evaluated by RT ‐q PCR in samples from 35 PC a, 24 adjacent non‐neoplastic prostate ( A dj P ) tissues, five cases of benign prostatic hyperplasia ( BPH ), and two histologically normal prostates ( N ). STEAP 1 expression was assessed by immunohistochemistry in samples from 198 PC a, 76 A djP, 22 BPH , and two N . The findings were compared with clinical and pathological parameters and patient outcome. STEAP 1 and STEAP 2 transcript analysis showed no differences between the groups tested. Although not significant, higher STEAP 1 m RNA levels were detected in tumours with high Gleason scores and in patients who presented with biochemical recurrence ( BCR ). STEAP 1 overexpression was detected in PC a, and was significantly associated with high‐grade G leason scores, seminal vesicle invasion, BCR , and worse outcome (metastasis or PC a‐specific death). STEAP 1 overexpression was significantly associated with shorter BCR ‐free survival. Multivariate analysis revealed that STEAP 1 is an independent marker for BCR . Conclusions These findings provide evidence that STEAP 1 is a biomarker of worse prognosis in PC a patients.