Abstract: Objective To investigate the relationship between apoptosis and cell proliferation and the expression of stat3 as well as their prognostic significance in colorectal carcinoma(CRC). Methods Samples from 129 patients with CRC and adjacent normal mucosa were analyzad for stat3 and CyclinD1 expression with immunohistochemistry, and the apoptotic index with TUNEL method. The association of stat3 expression with clinicopathological parameters, prognosis, apoptotic and proliferative activities was subsequently analyzed. Results The expression of stat3 and CyclinD1 showed significant difference (P＜0.05) between CRC tissues and adjacent non-cancerous tissues. The level of AI in CRC tissues was statistically lower than that in adjacent non-cancerous tissues (P＜0.05).The expression of stat3 was correlated with Dukes staging, lymph node metastasis and tumor location of CRC (P＜0.05).Stat3 expression was positively correlated with CyclinD1 (P＜0.05).Kaplan-Meier univariate analysis revealed stat3 positive expression, Dukes staging, lymph node metastasis and AI had significance for survival time（P＜0.05）. Cox model analysis revealed Dukes staging was a dangerous factor for independent prognosis of CRC. Conclusions Stat3 might participate in the development and progression of colorectal cancer. Stat3 protein can be acted as index to judge lymph node metastases and prognosis assessment of colorectal carcinoma.

Key words: Colorectal cancer, stat3, CyclinD1, apoptosis, prognosis