Objective: Detect the expressions of the protein tyrosine phosphatase gene (PTEN), phosphorylated protein kinase B (P-AKT) and phosphorylated extracellular signal-regulated kinase (P-ERK) in human middle ear cholesteatoma tissue and its correlation to explore their important role in the mechanism of the formation of cholesteatoma.
Method: Use immunohistochemical SABC method (SABC immunohistochemical method) to detect the expressions and location of PTEN, P-AKT and P-ERK proteins in 40 cases of middle ear cholesteatoma tissue samples and 15 cases of normal ear skin specimens. Use Western blot to detect the expression levels of PTEN, P-AKT, P-ERK proteins and the internal reference GAPDH in 20 cases of cholesteatoma tissue and 10 cases in nor mal ear skin specimens.
Result: (1) Immunohistochemistry showed coloring of PTEN both in the nucleus and cytoplasm of cholesteatoma and normal skin . Nuclear PTEN positive expression rates in the cholesteatoma was significantly lower than normal skin, and the difference was significant (P < 0.01); cytoplasm PTEN positive expression rates in the cholesteatoma was significantly lower than normal skin, and the difference was significant (P < 0.01); P-AKT mainly expresses in the cytoplasm of cholesteatoma and normal skin. The positive expression rates in the cholesteatoma was significantly higher than normal skin,and the difference was significant (P < 0.01); the P-ERK mainly colors in cholesteatoma and normal skin cell nucleus. the positive expression rates in the cholesteatoma was significantly higher than normal skin, and the difference was significant (P < 0.01). In cholesteatoma specimens, there was a significantly negative relationship (P < 0.01) between PTEN, respectively, and P-AKT, P-ERK protein. (2) Western blot discovered: the expression of PTEN in cholesteatoma was significantly less than the amount of expression in normal skin; P-AKT and P-ERK expression in cholesteatoma was significantly more than the level in normal skin.
Conclusion: Abnormal expression of PTEN, P-AKT and P-ERK protein in cholesteatoma may be closely related to antiapoptosis and high degree of proliferation in cholesteatoma. Expression of PTEN deletion leads to the weakening of the inhibition. Excessive expression of P-AKT gives rise to cholesteatoma epithelial cell apoptosis inhibited; excessive PERK expression result to cholesteatoma epithelial cell proliferation strengthened.