SOX2 gene expression in normal human thymus and thymoma.

The SOX gene family encodes a large group of transcription factors that are strongly involved in the normal human development and malignancies. Human tumors, like small cell lung carcinoma, meningioma, gastric, and pancreatic cancer, have been found to be immunogenic for SOX2 protein. In this study, we have investigated for the first time the expression and distribution of SOX2 immunoreactive cells in five normal human thymuses (2 fetal and 3 adult) and 10 thymomas bioptic specimens. Results demonstrated the presence of few positive cells in the fetal and postnatal normal human thymus with a specific distribution within thymus parenchyma compartments. On the contrary, in thymoma immunoreactivity to SOX2 increased parallel to pathological stage, and a peculiar distribution was observed in type B3 thymoma with a positive reaction in both tumor and endothelial cells.