{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Paired box protein 8 (PAX-8) is a transcription factor composed of a highly conserved N terminal DNA binding domain, an octapeptide, and a C terminal DNA binding domain. It plays crucial roles in embryonic development, particularly in the development of various organs such as the thyroid gland, kidneys, and reproductive system. PAX-8 regulates the expression of genes involved in cell differentiation and organogenesis, and is normally expressed in thyroid, renal tubules, and non-ciliated mucosal cells of the fallopian tubes. PAX-8 expression has been reported in tumors arising in the thyroid, including papillary thyroid carcinoma and follicular thyroid carcinoma. It is commonly detected in ovarian epithelial cells, which can help distinguish tumors of ovarian origin from metastases. PAX-8 expression has been observed in renal cell carcinoma, unlike other types of kidney tumors that normally do not express this biomarker."}]}]}