Background & objective: Cyclooxygenase-2 (COX-2) and signal transducers and activators of transcription (STAT) are closely correlated to the genesis of tumors. This study was to investigate the expression and clinical significance of COX-2, p-Stat3 and p-Stat5 (the activated forms of Stat3 and Stat5) in various lesions of esophageal tissues, and to analyze their correlations to clinicopathologic features of esophageal squamous cell carcinoma (ESCC).
Methods: The expression of COX-2, p-Stat3, and p-Stat5 in 59 specimens of ESCC, 24 specimens of squamous dysplasia, and 18 specimens of normal squamous epithelium was examined by SP immunohistochemistry. Their correlations to clinicopathologic features of ESCC were analyzed.
Results: The protein level of COX-2 was significantly higher in ESCC and squamous dysplasia than in normal squamous epithelium (2.10+/-1.77 and 1.85+/-1.24 vs. 0.83+/-0.46, P<0.05). The protein level of p-Stat3 was 0 in normal squamous epithelium, 0.76+/-0.59 in squamous dysplasia, and 2.83+/-1.27 in ESCC. The protein level of p-Stat5 was 1.98+/-0.78 in normal squamous epithelium, 3.92+/-0.41 in squamous dysplasia, and 5.02+/-0.34 in ESCC. There were significant differences among the 3 groups (P<0.05). In ESCC, COX-2 expression was correlated to lymph node metastasis and differentiation (P<0.05); p-Stat3 expression was correlated to tumor invasion depth (P<0.05); but p-Stat5 expression had no correlation to clinicopathologic features. COX-2 expression was positively correlated to both p-Stat3 expression and p-Stat5 expression in ESCC.
Conclusions: The up-regulation of COX-2, p-Stat3, and p-Stat5 may be correlated to the carcinogenesis of ESCC. The activation of Stat3 is correlated to the aggressive behavior of ESCC.