The findings demonstrating PDT-induced NO on the dysregulated NF-κB/Snail/YY1//RKIP loop suggested that inhibitors of NF-κB/Snail/YY1 or inducers of RKIP may be useful if used in combination with PDT for anti-tumor cell activity, and such studies are currently being explored. The gene discussed is YY1; the disease is neoplasm.