A Validation Study On Tissue Microarrays

Objectiv: To evaluate the validation of tissue microarrays by detecting the expression of Bax,GST-π,LRP,P-gp and TopoⅡin colorectal carcinoma on the tissue microarrays and the full tissue section. To evaluate the clinical significance of Bax, GST-π, LRP, P-gp and TopoⅡby detecting its expression in varying colorectal carcinoma.Method: Tissue microarrays with 2 mm in diameter tissue core were constructed from ninty cases of colorectal carcinoma. The tissue microarrays were stained for Bax, GST-π, LRP, P-gp and TopoⅡusing immunohistochemistry. At the same time the results on the tissue microarrays were compared with that from the full tissue sections. The statistical results were tested by SPSS 12.0.Results: A highly significant association was observed between the staining scores (0～7) obtained from the full tissue sections and from the tissue microarrays. Concordance of the whole section and the tissue core were respectively 90.91% for Bax, 92.05% for GST-π, 94.32% for LRP, 92.05% for P-gp and 89.77% for TopoⅡ. The discordance between full tissue sections and tissue microarrays had no statistical significance (P>0.05). The expression rate of Bax, GST-π, LRP, P-gp and TopoⅡwas no related to sex, age, site, histological grading, Duke's stage, invasive depth and metastasis of lymph nodes (P>0.05).Conclusion: Tissue microarays with 2 mmin diameter tissue core can represent full tissue section on immunohistochemistry study, if the tissue microarrays are constructed as standard method. We believe tissue microarray is a reliable and high-throughout tool for research. The expression of Bax, GST-π, LRP, P-gp and TopoⅡhas no relations with sex, age, site, histological grading, Duke's stage, invasive depth and metastasis of lymph nodes.