Although no saturation of 111In-BnDTPA-F3 cell association was observed in vitro [see Figure 1 in Additional file 1], it is also possible that saturation of the tumor cell membranar nucleolin by F3 peptides is responsible for the modest tumor uptake (3 and 19 μg of 111In-BnDTPA-F3 and 125I-F3 were injected, respectively, compared to 0.33 μg of 213Bi-(F3)2). Here, F3 is linked to neoplasm.