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

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).