AIM: To assess whether the molecular markers of malignant tumors could improve the understanding of tumor characteristics, and to observe the characteristics of expression of cell cycle markers Ki-67 and cydin A in esophageal carcinoma and to analyze the relationship between proliferative activity of cancer cells and clinicopathological factors.METHODS: Seventy of surgically resected esophageal squamous cell carcinoma (SCC) were examined by immunohistochemistry utilizing commercially available antibodies. Nuclear staining was regarded as a positive result. At least 50 fields in each tumor and non-tumor section were evaluated at a medium power (x200) to determine the proportion of tumor cells and the staining intensity of nuclei in the entire sections.RESULTS: Ki-67 and cyclin A were only expressed in base cells of normal esophageal mucosa. The positive immunostaining of nuclei of SCC was significantly higher than that in normal esophageal mucosa (t= 13.32 and t= 7.52,respectively, P＜0.01). The distribution of positively stained was more diffuse and stronger in poorly differentiated SCC. Both Ki-67 and cyclin A expressions were related to histological grades of tumors (t = 3.5675 and t = 3.916; t= 2.13, respectively, P＜0.05) but not to the sex and age of the patients, tumor size, lymphatic invasion, location, or stage grouping.CONCLUSION: The proliferative activity of cancer cells may be understood by immunohistochemistry of Ki-67 and cyclin A in Chinese patients with esophageal SCC. These cell cycle markers may serve as an indicator of cancer cell proliferation rate. The overexpression of cell cycle markers Ki-67 and cyclin A suggests the poor SCC differentiation in patients with esophageal carcinoma.
