NF-κB is one of the major transcription factors induced by PDT [194, 195, 235–239], although in some instances NF-κB was also found to be downregulated following PDT, such as in nasopharyngeal carcinoma (hypericin as photosensitizer) and breast cancer cell lines (C-phycocyanin as photosensitizer) [240, 241]. This evidence concerns the gene NFKB1 and breast cancer.