Abstract: Objective To investigate stat 3 phosphorylation and E-cadherin expression and their clinical significance in human epidermal non-melanoma cutaneous tumors. Methods Immunohistochemistry technique was applied to measure the expression of p-stat 3 and E-cadherin protein in 30 cases of skin squamous cell carcinomas (SCC), 20 cases of basal cell carcinomas (BCC), 20 cases of seborrhoeic keratosis (SK) and 20 cases of normal subjects. Results ① p-stat 3 protein was significantly increased in SCC and BCC (P<0.001), and the expression of stat 3 in SCC was significantly higher than that in BCC (P<0.05). ② p-stat 3 expression in poorly differentiated SCC was higher than that in well differentiated SCC (P<0.05). The positive rate of p-stat 3 expression was correlated with the depth of tumor invasion (P<0.05), whereas there was no correlation between the positive rate and tumor size. ③ E-cadherin expression was significantly deceased in SCC (P<0.001), and E-cadherin expression was lower in SCC than that in BCC (P<0.05). In SCC, the intensity of E-cadherin expression was correlated with the extent of tumor differentiation, while there was no correlation between the expression and the depth of tumor invasion and the tumor size. ④There was a negative correlation between the expression intensity of p-stat 3 and E-cadherin in SCC (r_s=-0.372, P<0.05). Conclusions The overexpression of p-stat 3 may play an important role in the development of epidermal tumors. The abnormal activation of stat 3 may be related to the potentials of tumor invasion in SCC.

Key words: Carcinoma, squamous cell, Carcinoma, basal cell, E-Cadherins, Transcription factors