Abstract: Objective: To detect the expression level of Claudin-1 and Claudin-7 in the lesions of actinic keratosis (AK) and squamocellular carcinoma（SCC）. Methods: The expression levels of Claudin-1 and Claudin-7 were detected by immunohistochemical method in the 30 normal tissues adjacent to cancer, 30 AK lesions, 30 SCC lesons in our hospital from November, 2014 to November, 2016. Results: In the samples of normal controls, AK and SCC, the positivity rates of Claudin-1 cells were 100%, 53.33% and 13.33% respectively, with significant differences among three groups (Ps<0.05). Claudin-7 was negatively expressed in normal skin tissues, AK and SCC. Conclusion: The expression level of Claudin-1 protein decreased gradually in the adjacent normal skin tissues, AK and SCC tissues, and the down-regulation of Claudin-1 protein expression may be related to the malignant transformation of epidermal tumors.

Key words: Claudin-1, Claudin-7, actinic keratosis, squamocellular carcinoma