Correlation between the protein expression levels of A‐kinase anchor protein95, p‐retinoblastoma (Ser780), cyclin D2/3, and cyclin E2 in esophageal cancer tissues

AIM: This study aimed to investigate the correlation between the expression of A-kinase anchor protein95 (AKAP95), p-retinoblastoma (phosphorylated Rb, p-Rb), cyclin D2, cyclin D3 and cyclin E2 in esophageal cancer tissues and clinicopathological indexes. METHOD: The protein expression levels of AKAP95, p-Rb, cyclin D2/3 and cyclin E2 in 40 esophageal cancer tissues were detected using immunohistochemistry, and the correlation between them was analyzed. RESULT: The percentage of p-Rb (Ser780)-, cyclin D2-, cyclin D3- and cyclin E2-positive samples was 62.50%, 70.00%, 67.50% and 60.00%, respectively. Also, the positive expression did not correlate with the histological type, histological differentiation or lymph node metastasis. The expression of AKAP95 and p-Rb (Ser780), p-Rb (Ser780) and cyclin D2 and p-Rb (Ser780) and cyclin D3 in esophageal cancer tissues was found to be correlated (P < 0.05). CONCLUSIONS: The expression of AKAP95 and p-Rb (Ser780), p-Rb(Ser780) and cyclin D2, and p-Rb (Ser780) and cyclin D3 in esophageal cancer tissue was correlated, suggesting that these proteins might play a synergistic role in cell-cycle progression. Cyclin D2/D3 and p-Rb (Ser780) were correlated whereas cyclin E2 and p-Rb (Ser780) were not, suggesting that p-Rb (Ser780) might be highly expressed and the Ser780 site of Rb protein might be phosphorylated in the early stage of the G1 phase. Ser780 was the site in the primary phosphorylation stage of several phosphorylation sites during stepwise phosphorylation (from primary to high phosphorylation).