The assay revealed that whereas PTN induces per se a significant decrease in tumour cell migration, the migration index was even more impaired after application of PDT (the migration index varied from 0.65 ± 0.04 for PTN treatment to 0.30 ± 0.03 for PTN-PDT), suggesting that both PTN and PTN-PDT would be potential inhibitors of metastasis. This evidence concerns the gene PTN and neoplasm.