(A) Analysis of cell proliferation (PCNA), MVD (endothelial cells), and apoptosis (TUNEL) in L3.6pl cells growing in the pancreas of nude mice. Mice were treated with vehicle (control), AEE788, gemcitabine, or the combination of AEE788 and gemcitabine. (B) Double immunofluorescence staining of CD31/PECAM-1 and TUNEL in pancreatic tumors from mice treated with the combination of AEE788 and gemcitabine. Endothelial cells (CD31+) stained red fluorescence and apoptotic cells (TUNEL+) stained green fluorescence. Colocalization of endothelial cells undergoing apoptosis yields yellow fluorescence.