Epac1, PDE4, and PKC protein expression and their correlation with AKAP95 and Cx43 in esophagus cancer tissues

BACKGROUND This study examined the expression of exchange protein directly activated by cAMP1 (Epac1), PDE4, and PKC in esophageal cancer tissues, and analyzed the association of each protein with the pathological parameters of the samples. METHODS Epac1, PDE4, and PKC protein expression was evaluated by PV-9000 two-step immunohistochemical techniques in 51 esophageal cancer specimens and 10 para-carcinoma tissues. RESULTS The positive expression rates of Epac1 and PKC in esophageal cancer tissues (62.7% and 68.6%, respectively) were higher compared to those in para-carcinoma tissues (20% and 20%, respectively) (P < 0.05). The positive expression rate of PDE4 in esophageal cancer tissues (54.1%) was higher than in para-carcinoma tissues (30%), (P > 0.05). Epac1, PDE4, and PKC protein expression levels were not associated with the extent of tumor differentiation and/or lymph node metastasis (P > 0.05). Epac1 protein expression levels correlated with PDE4, PKC, and AKAP95 protein expression levels. In addition, there was a correlation between PKC and Cx43 protein levels (P < 0.05). CONCLUSION The expression rates of Epac1, PDE4, and PKC protein in esophageal cancer tissues were significantly higher compared to the rates in para-carcinoma tissues, suggesting an association between these proteins and the development and progression of esophageal cancer. The correlations between these proteins also revealed that they may exert a synergistic effect during the development of esophageal cancer.