An anti-CEA antibody with affinity for cancerous lesions and labeled with ICG-sulfo-OSu can therefore be imaged using this infrared fluorescence endoscope. Specific antibodies tagged with ICG-sulfo-OSu can label cancer cells and can generate a strong enough fluorescent signal to detect small cancers when examined with an infrared fluorescence endoscope.

The anti-MUC1 antibody stained gastrointestinal cancer cells well, and nearly specific infrared fluorescence in cancer tissues was observed using the labeled anti-MUC1 antibody. The ICG-sulfo-OSu-labeled anti-MUC1 antibody has possible usefulness for the screening of cancer via infrared fluorescence endoscopy.

It was found that the ICG-ATT-labeled antibody was a more specific and sensitive marker than ICG-sulfo-OSu-labeled antibody, and that lower binding molar ratios of ICG-ATT were more useful for labeling the antibody.

No abstract

Videoendoscopy has not significantly advanced diagnostic accuracy beyond that attainable by conventional fiberscopy, with respect to microcarcinomas of the digestive tract. We suspected that after the labeling of these lesions with an agent detectable by videoendoscope, digital processing of the images could facilitate endoscopic diagnosis of microcarcinomas. We have developed a novel antibody labeled with an indocyanine green (ICG) derivative that is evident by videoendoscope. However, the binding of such an exogenous antibody in vivo to tumor surfaces has not been described. In this preliminary study, after transplanting human gastric cancer or colorectal cancer into nude mice, we successfully bound the tumors in vivo with an anti-MUC1 mucin antibody, as subsequently confirmed by the performing of immunohistochemistry with a secondary antibody. The antibody labeled with an ICG derivative may therefore be clinically useful in detecting gastrointestinal microcarcinoma by videoendoscopy.