Aberrant expression of Fas and FasL pro-apoptotic proteins in basal cell and squamous cell carcinomas

P>Background. Fas and FasL are cell-surface receptors involved in apoptosis. Aim. To investigate Fas and FasL expression levels in basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) to gain an insight into the mechanisms of Fas/FasL apoptosis and immune evasion in epidermal tumours. Methods. Real-time PCR and streptavidin-biotin immunohistochemistry techniques were used to detect Fas and FasL expression in BCC, SCC and normal skin specimens. Results. Fas and FasL mRNA expression and immunostaining levels were lower in the 21 BCC specimens than in normal skin, whereas they were higher in the 15 SCC specimens than in normal skin. Conclusion. FasL immunostaining correlated with the capability of the tumour to invade and metastasize; the absent or weak immunostaining in the BCC specimens correlated with low capability, and the strong staining in the SCC specimens correlated with high capability.