Fig. 2.

Effect of trastuzumab and cetuximab on the cell viability of tumor cells. The susceptibility of canine mammary gland tumor cells expressing EGFR and/or HER-2 to cetuximab and trastuzumab was investigated in a tetrazolium-based cell viability assay. SKBR3 and DU145 cells that had been reported to overexpress HER-2 and EGFR were used as positive controls. The viability of the tumor cells after treatment with trastuzumab, cetuximab, or human IgG isotype antibody was evaluated every 24 h for 96 h. Tumor cells incubated in media alone served as a control. The values represent the means ± standard deviation (SD) of five independent experiments, each tested in triplicate. *p < 0.05