GLI1, CTNNB1 and NOTCH1 protein expression in a thymic epithelial malignancy tissue microarray

Background/Aim: Thymic epithelial tumors (TET) are rare. Wingless and INT (WNT), NOTCH and sonic hedgehog pathway interactions between thymocytes and thymic stroma are important to thymus and T-cell development. We analyzed a thymoma tissue microarray (TMA) for glioma associated oncogene homolog 1 (GLI1), NOTCH1 and catenin (cadherinassociated protein, beta 1) (CTNNB1) expression as surrogate markers of sonic hedgehog, NOTCH and WNT pathway activity. Materials and Methods: GLI1, NOTCH1 and CTNNB1 expression were assayed in a tissue microarray of 68 TET and eight benign thymus by fluorescent immunohistochemistry (AQUA) as surrogates for activity of the sonic hedgehog, NOTCH and WNT pathways respectively. Results: No difference in tumor GLI1 (mean 201 vs. 211, p=0.31), CTNNB1 (mean 222 vs. 306, p=0.66) or NOTCH1 expression (mean 317 vs. 325, p=0.82) was noted between thymic tumor and benign thymus. Conclusion: No evidence for preferential expression of GLI1, NOTCH1 or CTNNB1 was noted. High-throughput immuno - fluorescence using AQUA technology can help overcome limitations of small sample size and tissue heterogeneity when analyzing protein expression in thymic tumors.