The above findings demonstrated clearly that treatment of B78-H1 tumor cells with PDT resulted in cytotoxicity via inhibition of the constitutively activated NF-kappa B pathway, responsible for cell proliferation and viability, and downstream inhibition of its target gene product, Snail, and resulting in the derepression of the metastasis suppressor gene product RKIP. The gene discussed is PEBP1; the disease is neoplasm.