Characterization of ZAG protein expression in prostate cancer using a semi-automated microscope system

Abstract

Objective: Zinc-alpha-2-glycoprotein 1 (ZAG) is a 41-kD secreted protein that is known to stimulate lipid degradation in adipocytes. The aim of this study was to determine how ZAG protein expression is associated with prostate cancer (PCa).

Materials and methods: An immunohistochemistry analysis was performed on a 227 PCa tissue microarray cases. ZAG protein expression was assessed using a semi-automated cellular image analysis system.

Results: ZAG expression was associated with tumor stage (pT2 > pT3 > metastasis cases, P < 0.001), and was inversely associated with Gleason score on pathology (P = 0.01). ZAG intensity was predictive of biochemical recurrence (P = 0.002). On multivariate analysis including pT2 patients, the predictive factors of biochemical recurrence were ZAG expression (P = 0.016), Gleason score (P = 0.011), and surgical margin status (P = 0.047).

Conclusions: This study characterized ZAG protein expression in PCa using a semi-automated system. ZAG expression level found to have an independent prognostic value for pT2 patients.