Proliferation and apoptosis of tumor β-cells treated with [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 and/or imatinib. (A) Proliferation of tumor beta-cells of Rip1Tag2 mice treated with [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 and [Lys40(Ahx-DTPA-111In)NH2]-exendin-4 plus imatinib is reduced compared to the natIn-exendin-4 and the imatinib group (*p < 0.05, Newman-Keuls post-test). (B) However, the combined treatment modality does not increase tumor cell apoptosis compared to the other groups (p > 0.05, Newman-Keuls post-test). (C) Immunohistochemistry for proliferation (BrdU, top row) and apoptosis (TUNEL, bottom row) on the sections of Rip1Tag2 pancreas treated as indicated on the graph. Size bars, 100 μm.