RAB5A and pancreatic neoplasm: Immunofluorescence co-staining of the cultivated pancreatic tumor cells of Rip1Tag2 mice incubated 30, 60, 120, and 240 min with fluorescein-Trp25-exendin-4 and stained with antibodies against Rab5 (early endosome), Rab7 (late endosome), or LAMP-2 (lysosome) indicates that cellular uptake of exendin-4 is not strongly correlated with the endosomal (Figure 2) or the lysosomal pathway (Figure 3).