The interplay of UV and cutaneous papillomavirus infection in skin cancer development
Fig 2
Histological analyses of a non-UV tumor and UV-induced tumors.
A) Tumors from unirradiated sites show papilloma-like growth of well-differentiated neoplastic squamous cells (H&E). Especially the basal layers are hyperproliferative as indicated by strong Ki-67 staining. Throughout all layers of the lesion, neoplastic cells strongly express cytokeratins (pan-Cytokeratin). B) A UV-induced KSCC with well-differentiated exoendophytic proliferations of squamous cells expressing Ki-67 throughout all neoplastic squamous layers. C and D) In some cases well-differentiated KSCCs (C) further developed into more aggressive poorly differentiated nKSCCs (D). Proliferating altered squamous cells thereby invaded deeper layers and often changed to a spindle-like phenotype (H&E). The Ki-67 staining becomes diffuse in this process (compare insets) and cytokeratin expression is reduced. (d: dermis; e: epidermis; f: fat; k: keratin; m: muscle; u: ulceration; t: tumor. Scale bars: macroscopic: 10 mm, overviews: 1 mm, insets 100 μm).