Low-molecular-weight protein tyrosine phosphatase expression as a prognostic factor for men with metastatic hormone-naïve prostate cancer

Objectives: Recent studies have demonstrated that up-front docetaxel combined with androgen deprivation therapy (ADT) prolongs survival in some patients with metastatic hormone-naïve prostate cancer (mHNPC). However, new biomarkers for selecting personalized treatment strategies for mHNPC are warranted. We evaluated the value of low-molecular-weight protein tyrosine phosphatase (LMW-PTP) expression as a prognosticator in men with mHNPC.

Methods and materials: A total of 48 men with mHNPC diagnosed from 2003 to 2009 were enrolled in this study. Prostate cancer tissues obtained by needle biopsies were immunohistochemically stained for LMW-PTP. Correlations between LMW-PTP expression and clinicopathological characteristics were then assessed.

Results: At the time of analysis, 29 (60.4%) patients were alive, whereas 15 (31.3%) and 4 (8.3%) died of prostate cancer and nonprostate cancer, respectively. Of these, 29 (60.4%) had low LMW-PTP expression and 19 (39.6%) had high expression. Median overall survival (OS) for patients with high LMW-PTP expression was not reached and that for patients with low LMW-PTP expression was 23.8 months. High LMW-PTP expression was significantly correlated with a shorter OS compared with low LMW-PTP expression (P = 0.01). Moreover, multivariate analysis showed that Gleason score (≥8 vs.≤7; HR = 5.8, 95% CI: 1.3-26.5, P = 0.02) and LMW-PTP expression (high vs. low; HR = 2.7, 95% CI: 1.0-7.2, P = 0.04) were independent prognostic factors for OS.

Conclusions: LMW-PTP is a potential biomarker to predict OS in patients with mHNPC.