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Proteome analysis and tissue array for profiling protein markers associated with type B thymoma subclassification Full Text
Chinese Medical Journal, 08/21/2012
Qiang–ling S et al. – Differentially expressed proteins between type B1 and B2 thymoma tissues were analyzed by comparative proteomic analysis. The techniques of proteomic analysis and tissue array provide a potential tool for screening of key molecules in type B thymoma histological sub–classifications. The statistical analysis of ezrin and GSTP1 expression by immunohistochemistry, especially GSTP1, may be a useful approach for type B thymoma classification.
Methods- Proteins extracted from twelve type B thymoma tissue specimens (six type B1 and six type B2) were analyzed by two–dimensional electrophoresis (2–DE) coupled with MALDI–TOF–MS.
- Differentially expressed proteins were then assayed in sixty–nine type B thymoma tissues (including B1, B2 and B3) by tissue array analysis with immunohistochemistry staining.
- The relationship of their expression with clinicopathological parameters, such as tumor stage or WHO classification, was estimated by Spearman’s Rank Correlation Test.
- Sixteen differentially expressed proteins between type B1 and B2 thymoma tissues were identified.
- The differential levels of ezrin and glutathione S–transferase pi (GSTP1) were validated using immunohistochemistry staining.
- A statistically significant difference was observed in the positive rate of ezrin expression between type B1 thymoma and type B3 thymoma (Z= –2.963, P <0.01).
- Ezrin showed a tendency to be expressed in higher classification tumors from type B1 to B3.
- A statistical analysis demonstrated that type B2 and B3 tumors had significantly higher positive expression of GSTP1 than the B1 group (type B2 vs. B1: Z= –2.582, P ≤0.01; type B3 vs. B1: Z= –4.012, P ≤0.001).
- The results also showed a strong correlation between GSTP1 and WHO type staging of B1 to B3 tumors (Spearman’s correlation coefficient: 0.633, P ≤0.001).
- Statistical analysis showed that there was close correlation between GSTP1 and ezrin expression with the clinical stage (Spearman’s correlation coefficients, ezrin: 0.481, P <0.05; GSTP1: 0.484, P <0.01).