Figure 5.

Gemcitabine in combination with erlotinib in recurrent tumors of PANC-1 cells induces increased activity of caspase-3 and caspase-9. (A and B) Immunohistochemical staining of active caspase-9 and active caspase-3 in tumor tissue sections revealed active caspase-9 activation by either the monotherapy and by the combination treatment and active-caspase-3 activation by erlotinib monotherapy and by the combination treatment in PANC-1 cells. Lower panels displayed higher magnification (original magnification, ×400) of the boxed areas in the upper panels. Scale bars, 10 µm. (C and D) Visual fields (4–6) in each section of irradiation were photographed. The staining intensity and the percentage of positive cells were calculated and scored in each section. The total scores in each visual field were first analyzed using the homogeneity of variance test, followed by the change of variable test. The scores were presented as the mean ± SD. GraphPad Prism 5 was used to plot cartograms. *P<0.05 indicates the controls vs. the treatment groups. ^#P<0.05 indicates the monotherapy (E or G) vs. the combination (E+G) groups.