Issues

The cover displays a near-infrared photographic image produced by a small-animal fluorescence imaging system (Olympus, Tokyo, Japan) of cathepsin expression marked by Prosense in the small bowel of a mouse. Cathepsin proteins are cysteine proteases and have been implicated in cancer pathogenesis. Prosense is a non-fluorescent macromolecule that is activated and becomes fluorescent through cleavage by cathepsins. Activated Prosense shows up in the adenoma (where false-colored red and orange reflect areas of greater near-infrared signal intensity) but not in the surrounding normal mucosa (where false-colored violet and blue reflect areas of less signal). Therefore, cathepsin activity occurred selectively in the adenoma site. Increased expression of cathepsins B and D also occurred in the plasma of adenoma-bearing mice and in mouse adenoma tissue assessed immunohistochemically. See article by Hung et al. (beginning on page 224) for more information.