Solar ultraviolet (UV) radiation is an important risk factor in skin carcinogenesis. Progression of cutaneous squamous neoplasms from actinic Keratosis (AK) to Bowen's disease (BD) has important implications for clinical management and treatment, thus requiring accurate diagnosis.The induction of skin cancer is mainly caused by the accumulation of mutations caused by UV damage. Cellular mechanisms exist to repair the DNA damage or to induce apoptosis to remove severly damaged cells; however the additive effects of mutations in genes involoved in these machanisms or in control of the cell cycle can lead to abnormal cell proliferation and tumor development.This study aim to evaluating the expression of p53, COX-2, EZH-2 and Factor VIII in Squamous cell carcinoma, Actinic Keratosis and Bowen Disease speciments of the skin.Skin surgical speciments of 106 patients were evaluated in these case groups including AK, BD and SCC.Immunohistochemical staining was performed in all the speciments and the expression rates and patterns of COX-2, p53, EZH-2 and Factor VIII were determined using an image analysis system on stained slides.The intensity of immunostain for COX-2 was inversely proportionate of extension area of stain. The extension of the immunostain for COX-2 correlated with the percentage (%) of positive nucleus for EZH-2 (p<0,0001) and p53 (p<0,0001). The mean value of intensity of COX-2 staining correlated with histological type (p=0,031) and was lower for SCC than AK. The mean value of extension of staining for COX-2 correlated with histological type and was greater for SCC than AK. The % of positive nucleus for EZH-2 and p53 correlated with histological type (p=0,015 and p=0,006 respectively). The value was greater in SCC than AK. The intensity of immunostaining for COX-2 no correlated with the degree of dysplasia of AK (p=0,542) and the differentiationof SCC (p=0,684). The mean value of staining extension for COX-2 was greater in severe AK than mild (p=0,003) and in grade IV than smaller grades (p=0,001). The mean value of the % of positive nucleus for EZH-2 and p53 was greater in severe than mild AK (p=0,015 and p=0,010 respectively). The mean value of % of positive nucleus for EZH-2 and p53 was greater in grade IV than I, II, III grades (p=0,003 and p=0,014 respectively).For the Factor VIII the statistical analysis showed a relationship with the histological type of the tumor. The mean value for Factor VIII was statistical significant different for SCC in relationship with AK (p<0,0001) and Bowen's disease (p=0,018). This value was higher in SCC than BD (32,2) was higher than AK (17,83).The knowledge gained with the study of biological markers will help to better unsterstand the ways in which skin cancer arises for UV exposure, which will in turn development of better methods of treatment and prevention.