(A) Relative expression of Cath E in 293FT and MPanc96-E tumor cell lines; (B) in vivo fluorescence image of Cath E-positive 293FT/MPanc96-E tumor xenografts in Nu/Nu mice after 48 h of 2 nmole administration of Cath E selective probe a; (C) ex vivo bright and fluorescence image of excised representative organs and tissues 48 h post injection; 1, 293FT-tumor; 2, pancreas; 3, kidney; 4, small intestine; 5, muscle; 6, lung; 7, MPanc96-E pancreatic tumor.