Update on the pathogenesis of squamous cell carcinoma development in recessive dystrophic epidermolysis bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a recessively inherited blistering disorder due to mutations in the collagen VII gene, COL7A1. Patients with RDEB have up to a 50 fold increased incidence of cutaneous squamous cell carcinoma (cSCC) which is independent of ultraviolet (UV) exposure. The pathogenesis of cSCC development and its aggressive nature in RDEB remain unclear. To date there is no convincing evidence that RDEB SCC and UV SCC are distinct. A recent discovery of a remarkably distinct tumour microenvironment in part explains the aggressive nature of RDEB SCC and the importance of collagen VII expression as a potential therapeutic measure. The role of gram negative flagellate bacteria increasing the risk of SCC development in chronic wounds has recently been elucidated in RDEB.