Loss of expression of AZGP1 is associated with worse clinical outcomes in a multi-institutional radical prostatectomy cohort.

Given the uncertainties inherent in clinical measures of prostate cancer aggressiveness, clinically validated tissue biomarkers are needed. We tested whether Alpha-2-Glycoprotein 1, Zinc-Binding (AZGP1) protein levels, measured by immunohistochemistry, and RNA expression, by RNA in situ hybridization (RISH), predict recurrence after radical prostatectomy independent of clinical and pathological parameters.

AZGP1 IHC and RISH were performed on a large multi-institutional tissue microarray resource including 1,275 men with 5 year median follow-up. The relationship between IHC and RISH expression levels was assessed using the Kappa analysis. Associations with clinical and pathological parameters were tested by the Chi-square test and the Wilcoxon rank sum test. Relationships with outcome were assessed with univariable and multivariable Cox proportional hazards models and the Log-rank test.

Absent or weak expression of AZGP1 protein was associated with worse recurrence free survival (RFS), disease specific survival, and overall survival after radical prostatectomy in univariable analysis. AZGP1 protein expression, along with pre-operative serum PSA levels, surgical margin status, seminal vesicle invasion, extracapsular extension, and Gleason score predicted RFS on multivariable analysis. Similarly, absent or low AZGP1 RNA expression by RISH predicted worse RFS after prostatectomy in univariable and multivariable analysis.

In our large, rigorously designed validation cohort, loss of AZGP1 expression predicts RFS after radical prostatectomy independent of clinical and pathological variables. Prostate © 2016 Wiley Periodicals, Inc.

The Prostate. 2016 Jun 21 [Epub ahead of print]

James D Brooks, Wei Wei, Jonathan R Pollack, Robert B West, Jun Ho Shin, John B Sunwoo, Sarah J Hawley, Heidi Auman, Lisa F Newcomb, Jeff Simko, Antonio Hurtado-Coll, Dean A Troyer, Peter R Carroll, Martin E Gleave, Daniel W Lin, Peter S Nelson, Ian M Thompson, Lawrence D True, Jesse K McKenney, Ziding Feng, Ladan Fazli

Department of Urology, Stanford University, Stanford, California., Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas., Department of Pathology, Stanford University, Stanford, California., Department of Pathology, Stanford University, Stanford, California., Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California., Department of Otolaryngology-Head and Neck Surgery, Stanford University, Stanford, California., Canary Foundation, Canary Center at Stanford, Palo Alto, California., Canary Foundation, Canary Center at Stanford, Palo Alto, California., Department of Urology, University of Washington Medical Center, Seattle, Washington., Department of Pathology, University of California San Francisco, San Francisco, California., Department of Urologic Sciences and Vancouver Prostate Centre, Vancouver, British Columbia, Canada., Department of Pathology, University of Texas Health Science Center at San Antonio, San Antonio, Texas., Department of Urology, University of California San Francisco, San Francisco, California., Department of Urologic Sciences and Vancouver Prostate Centre, Vancouver, British Columbia, Canada., Department of Urology, University of Washington Medical Center, Seattle, Washington., Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington., Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas., Department of Pathology, University of Washington Medical Center, Seattle, Washington., Department of Pathology, Cleveland Clinic, Cleveland, Ohio., Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas., Department of Urologic Sciences and Vancouver Prostate Centre, Vancouver, British Columbia, Canada.