 Light illumination is applied at 24 h post drug infusion to enable sufficient time for the drug to distribute in the tumor after administration. Cell killing occurs only at cancer cells expressing the protein EGFR that is bound to the drug RM-1929. The requirement of binding of the drug to EGFR of cancer cells enables the selective destruction of cancer cells with minimum damage of healthy tissue surrounding the tumor cells. Preclinical pharmacology demonstrated that light-induced activation of RM-1929 elicits rapid tumor destruction of human cancer xenografts implanted in mice and that the treatment is cancer specific. 