The early upregulation of activin during epithelial skin tumorigenesis in mice and humans may be a consequence of inflammation, since activin A expression is induced in cultured keratinocytes by pro‐inflammatory cytokines (Hubner & Werner, 1996) and since AK lesions and also papillomas in HPV8‐transgenic mice are characterized by an inflammatory infiltrate (Massone & Cerroni, 2015; Rolfs et al, 2015; M. Antsiferova and S. Werner, unpublished data). Here, INHBE is linked to papilloma.