GSK3B and neoplasm: Tumor lysates from all the treatment groups in the xenograft study were analyzed for CXCR6, β-catenin, and GSK3β protein levels using Western blotting (Figure 2A).Analysis of GSK3β, a central negative regulator of Wnt/β-catenin signaling, revealed a modest reduction in the ratio of phosphorylated GSK3β (inactive form) to total GSK3β in SBI-457-treated tumors, suggesting a trend toward increased GSK3β activity (Figure 2B; File S1).