We have developed a tumor-targeting dye that has shown activity in over 30 different cancer types, bound to chemotherapy drugs, by a linker, which deactivates the drug until it reaches the tumor. Once the drug is delivered by the dye to the tumor, the linker dissolves in the tumor micro-environment, releasing the drug, activating it. Our xenograft data shows dramatic safety enhancements with equivalent efficacy to the unprotected chemo drug.