Figure 1.

Schematic presentation of the cross-talk between beta-HPVs and the cell-autonomous or extrinsic immune system that may determine disease penetrance and progression to skin cancer. In healthy epithelium, Langerhans cells are present; during beta-HPV-driven co-carcinogenesis and progression to invasive cancer, the local immune system is deregulated and the stroma becomes infiltrated with myeloid cells. Red nuclei indicate ΔNp63-positive progenitor/stem cells. CCL20, CC-chemokine ligand 20; C/EBP, CCAAT/enhancer-binding protein; CIB1, calcium- and integrin-binding protein 1; cSCC, cutaneous squamous cell carcinoma; DDR, DNA damage response; HPV, human papillomavirus; IRF, interferon regulatory factor; OTRs, organ transplant recipients; TLR, Toll-like receptor; UV, ultraviolet.