Schematic overview. Shown is a schematic diagram of the possible relationship among the pro-inflammatory mediator HMGB-1, MMP-9, PAR-2, and the chemokine IL-8 to establish a hyperplastic environment within the skin that might participate in ALK⁺ lymphoma cell epidermotropism and cutaneous metastasis development. Solid arrows indicate pathways established by our data; dashed arrows are currently supported only by circumstantial evidence and remain to be experimentally validated. Illustration done by Servier Medical Art (http://www.servier.fr/servier-medical-art).