Objective:To investigate the expression of pSTAT3 protein and STAT3 mRNA and their significance in cutaneous melanoma. Methods:The expression of pSTAT3 protein and STAT3 mRNA was examined in 90 cases of melanoma and 47 cases of nevus by immunohistochemistry and in situ hybridization, respectively. Results:The positive rates of pSTAT3 protein and STAT3 mRNA were 56.7% and 47.8%, which were significantly higher than those in the nevus. Both the expression of pSTAT3 protein and STAT3 mRNA were significantly correlated to depth of tumor invasion and tumor lymph node metastasis. Moreover, a significant correlation was found between the expression of pSTAT3 protein and STAT3 mRNA in melanoma. Conclusion:The expression of STAT3 was closely correlated to the tumor growth, invasion and metastasis, suggesting STAT3 might play an important role in the cutaneous melanoma development and progression.