Relationship between proliferative activity of cancer cells and clinicopathological factors in patients with esophageal squamous cell carcinoma

Abstract

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 cyclin 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 immuno-staining 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.

Figure 1

Ki-67 and cyclin A staining patterns in human normal esophageal mucosa and esophageal SCC. A and E: Negative control in normal esophageal mucosa; B and F: positive nuclear staining in normal esophageal mucosa; C and G: moderately differentiated SCC; D and H: poorly differentiated SCC. Positive nuclear staining was located in base cells in normal mucosa. The diffuse and strong Ki-67 immunostaining in esophageal SCC and the higher SI of the poorly differentiated SCC were found compared with the other carcinomas. Counterstaining with hematoxylin, ×200.