GCG and type 2 diabetes mellitus: Proportion of GLP‐1 expressing cells showed a positive correlation with blood HbA1C concentration (Figure 3; all subjects including controls r = 0.454, p = 0.005; all patients r = 0.443, p = 0.015; T2D patients r = 0.580, p = 0.014; patients without T2D r = 0.281, p = 0.331; controls r = 0.359, p = 0.553), and with plasma glucose concentration during meal test in all subjects (0 min: r = 0.379, p = 0.028; 30 min: r = 0.382, p = 0.028; 60 min: r = 0.487, p = 0.018; 120 min: r = 0.392, p = 0.028, AUC r = 0.455, p = 0.0018; incremental AUC r = 0.442, p = 0.018).