Fig. 3

Human epidermal growth factor receptor 2 (HER2)-specific accumulation of trastuzumab-IR700 conjugate (Tra-IR700) in vivo. a Tra-IR700 distribution over time was assessed using an in vivo imaging system. NCI-N87 tumors (right dorsum) were clearly and selectively visualized by IR700 fluorescence as early as 1 day after Tra-IR700 injection. Conversely, MKN-45 tumors (left dorsum) were only weakly visualized by IR700 fluorescence, and the signals gradually attenuated over time (n = 5 mice). b Fluorescence intensity of IR700 in NCI-N87 tumors, MKN-45 tumors, and background. Data are presented as means ± SEM (n = 5 mice, ** P < 0.01 vs. MKN-45 tumors, Student’s t test). c Tumor-to-background ratios of IR700 fluorescence intensity in NCI-N87 and MKN-45 tumors. Data are presented as means ± SEM (n = 5 mice, ** P < 0.01, *** P < 0.001 vs. MKN-45 tumors, Student’s t test)