The comparison of squamous cell carcinoma cells of an RDEB patient with those of a non-EB patient shows a 2-3 times higher fluorescence of A431 cells after PpIX formation and after 3 μM hypericin accumulation, and an up to 8 times higher fluorescence after 5 μM hypericin, for both pretreatment conditions (with and without TNF-alpha induction) (Figures 15(a)–15(d)). Here, TNF is linked to squamous cell carcinoma.