[Cancer immunophotodetection and immunophototherapy].

Some dyes can be used for cancer diagnosis and therapy. Following administration, the dye concentrate with some specificity in the tumor and can react to an irradiation with light. Some excited dyes can be fluorescent allowing detection of very small tumors. Some other dye can be phototoxic and lead to the destruction of the tumor. These attractive techniques are however limited because of the too low tumor specificity of the currently used dyes (hematoporphyrin and phthalocyanine). A new strategy has be developed in which the fluorescent or phototoxic dye is coupled to an antibody directed against a tumor associated antigen. This approach allow the selection of the dye only for its optimal photochemical properties, the antibody being used as carrier to concentrate the dye in the tumor. Many experimental immunophototherapy studies have been performed with different phototoxic dyes. Some results are encouraging but the involved mechanisms are complex and they limit the current clinical applications of immunophototherapy. Concerning immunophotodetection, two dyes have been coupled to anti-tumor antibodies: fluorescein and indocyanin. The antibody-dye conjugates have been evaluated in experimental studies and in pilot clinical trials. The most recent results concern the use of this technique in intraoperative situation and to visualize neo-vascularization. Immunophotodetection gives a very precise image of tumors. The detected tumor nodules are in the millimeter range. However, according to the limited light pathway in the tumor, this technique can be applied only to cutaneous areas, endoscopy accessible areas and intraopearative situations. Immunophotodetection is an attractive imaging technique using antibodies.