Glycogen Synthase Kinase 3 Beta Predicts Survival in Resected Adenocarcinoma of the Pancreas.

PURPOSE GSK3β is a protein kinase that can suppress a number of key oncoproteins. We have previously shown in preclinical models of pancreatic ductal adenocarcinoma (PDAC) that inhibition of GSK3β causes stabilization and nuclear translocation of β-catenin, poor differentiation, proliferation, and resistance to radiation. The objective of this study was to determine its utility as a biomarker of clinical outcomes. EXPERIMENTAL DESIGN Automated Quantitative Immunofluorescence Analysis (AQUA) of GSK3β was performed on a tissue microarray with samples from 163 patients treated on RTOG 9704. On the basis of findings in an exploratory cohort, GSK3β was analyzed as a categorical variable using its upper quartile (>Q3) as a cut point. Overall survival (OS) and disease-free survival (DFS) were estimated with the Kaplan-Meier method, and GSK3β groupings were compared using the log-rank test. Univariable and multivariable Cox proportional hazards models were used to determine associations between GSK3β and OS/DFS. RESULTS The 3-year OS rates for GSK3β≤Q3 versus GSK3β >Q3 were 16% (95% confidence intervals; CI, 10%-23%) and 30% (95% CI, 17%-44%), respectively, P = 0.0082. The 3-year DFS rates were 9% (95% CI, 5%-15%) and 20% (95% CI, 9%-33%) respectively, P value = 0.0081. On multivariable analysis, GSK3β was a significant predictor of OS. Patients with GSK3β >Q3 had a 46% reduced risk of dying of pancreatic cancer (HR, 0.54; 95% CI, 0.31-0.96, P value = 0.034). The HR for DFS was 0.65 (95% CI, 0.39-1.07; P value = 0.092). CONCLUSIONS GSK3β expression is a strong prognosticator in PDAC, independent of other known factors such as tumor (T) stage, nodal status, surgical margins and CA19-9. Clin Cancer Res; 21(24); 5612-8. ©2015 AACR.