Relationship between intracellular localization of p34^cdc2 protein and differentiation of esophageal squamous cell carcinoma

Purpose: G2/M cyclins including cyclins A and B can exert their biologic functions of mitosis and proliferation of the tumor cells by being combined by protein kinase p34cdc2. The aim of the current study was to elucidate the clinicopathologic significance of immunohistochemical expression of p34 ^cdc2 in esophageal squamous cell carcinoma (ESCC), which has not been resolved. Methods: Immunohistochemical expression of p34^cdc2 was examined for 91 cases of ESCC, and the relationship between the type of p34 ^cdc2 expression and the clinicopathologic features of the patients and tumors was analyzed. Results: Forty-one ESCCs demonstrated cytoplasm dominant expression of p34^cdc2 and the other 50 ESCCs showed nuclei dominant p34^cdc2 expression. This differential expression pattern of p34^cdc2 did not reflect a prognostic aspect; however, the proportion of keratinizing tumors ESCCs with cytoplasm dominant expression of p34 ^cdc2 was significantly higher than that among ESCCs presenting nuclei-dominant p34^cdc2 expression (P = 0.006). Conclusion: Cellular differentiation in squamous cell carcinoma of the esophagus may be mediated by an intracellular localization of p34^cdc2.