PAX8 is one of nine transcription factors within the PAX gene family. It has been observed to be expressed during embryonic development however expression attenuates after development in all but a few tissues. Research has indicated that over-expression of PAX proteins in general are not an initiating event in tumorgenesis however they may facilitate malignant development. PAX8 is expressed in 80-96% of all High-grade serous carcinomas (HGSC) and is commonly used as a marker for the disease. In addition PAX8 has become a useful biomarker for differentiating between mullerian mucinous and non-mullerian tumors. PAX8 has also been associated with neoplasms in the kidney and thyroid.
