Figure 4: Optical Imaging and quantification. (a) In vivo fluorescence imaging of subcutaneous PLC/PRF/5 (labeled as PLC5 in the figure), Hep3B, and HepG2 tumor-bearing nude mice at prescan, 1 h, 2 h, 4 h, and 24 h p.i. Approximately 500 pmol Alex680- was injected. Arrows indicate the location of tumors. (b) ROI analysis of tumor and normal tissue (muscle) fluorescence flux and tumor-to-muscle ratio after tail vein injection of Alex680- in mice bearing PLC/PRF/5 tumor (). (c) Protein extractions from subcutaneous tumor tissues were harvested and assessed for EGFR expression. Bands for EGFR and β-actin are indicated by arrowheads. Protein ladders are indicated in kDa. (d) Contrast of in vivo fluorescence imaging of subcutaneous PLC/PRF/5 tumor-bearing nude mice at 2 h and 4 h. Alex680- with (right) or without (left) coinjection of unlabeled Ac-Cys- (300 μg). (e) Fluorescence intensity ratio of tumor to muscle in blocking and unblocking PLC/PRF/5 tumor-bearing nude mice at 2 h and 4 h p.i. (f) Ex vivo imaging of tumor and normal tissues of PLC/PRF/5 tumor-bearing animals injected with Alex680- and sacrificed at 24 h p.i.. Tm: tumor; H: heart; L: lung; Lv: liver; Sp: spleen; Kn: kidney; St: stomach; Ins: intestine; Br: brain; Bo: bone; Ms: muscle.