Proteinase-activated receptor-2 expression in basal and squamous cell carcinomas compared with normal skin.

Proteinase-activated receptor-2 (PAR-2) is a transmembrane G-protein expressed in many normal tissues and overexpressed in several cancer cell lines. It contributes to metastasis, promotes epidermal growth factor receptor proliferation, angiogenesis and tumor progression in many carcinomas. The purpose of this study was to investigate the expression of PAR-2 in basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in comparison with that of normal skin. Immunohistochemical (IHC) expression of PAR-2 was examined using paraffin-embedded sections from 30 BCCs, 30 SCCs and also 30 normal sun-exposed skin specimens. PAR-2 was expressed in all specimens of SCC and normal skin. In marked contrast, all BCC specimens had negative IHC staining. Given the important role of PAR-2 in angiogenesis and metastasis, our finding can explain the far less aggressive behavior of BCC as compared with SCC.