Prediction of Time to Castration-Resistant Prostate Cancer Using Low-Molecular-Weight Protein Tyrosine Phosphatase Expression for Men with Metastatic Hormone-Naïve Prostate Cancer.

Introduction: Low-molecular-weight protein tyrosine phosphatase (LMW-PTP) expression affects carcinogenesis in various cancers and has been associated with determining the overall survival among men with metastatic hormone-naïve prostate cancer (mHNPC). In this study, we analyzed the value of LMWPTP for prediction of time to castration-resistant prostate cancer (CRPC) for men with mHNPC.

Materials And Methods: We retrospectively enrolled 45 men with mHNPC who were diagnosed from 2003 to 2009. All patients had received androgen deprivation therapy as first-line treatment. Prostate cancer tissues (pre-treatment needle biopsies) were immunohistochemically stained for LMW-PTP. Multivariate analyses (Cox proportional hazard model) were used to correlate baseline clinical factors of age, prostate-specific antigen (PSA), Gleason scores, T stage, N stage, extent of disease on bone scan (EOD), LMW-PTP expression and time to CRPC. Continuous variables were classified as dichotomous.

Results: Median age and PSA were 70.0 years and 87.8 ng/mL respectively. Median time to CRPC was 40.2 months. Median time to CRPC was significantly shorter in the high LMW-PTP group (14.8 months) than that in the low LMW-PTP group (86.3 months, p < 0.01). In multivariate analysis, age ≥70 years and high LMW-PTP expression were significant predictors of time to CRPC.