The Pathology Dictionary Team
May 22, 2023
PAX8 (Paired box gene 8) is a specialized protein called a transcription factor. It plays an important role in the formation of various organs including the thyroid gland, kidneys, ovaries, fallopian tubes, uterus, and vagina.
The PAX8 protein is required for the normal development and function of various organs including the thyroid gland, kidneys, ovaries, fallopian tubes, uterus, and vagina. In the thyroid gland, PAX8 regulates the expression of genes that are necessary for the production of thyroid hormones, such as thyroxine (T4) and triiodothyronine (T3).
PAX8 is expressed by normal, healthy cells in the thyroid gland, kidneys, ovaries, fallopian tubes, uterus, and vagina. PAX8 is also expressed by some types of immune cells.
Organs that normally show expression of PAX8 include:
PAX8 expression is commonly seen in a wide variety of noncancerous and cancerous tumours, and its immunohistochemical detection is often used as a diagnostic marker for these types of tumours.
Tumours that express PAX8 include:
It’s important to note that while PAX8 expression is observed in these tumour types, it should be interpreted in conjunction with other clinical and pathological features for accurate diagnosis and management.
Pathologists use a test called immunohistochemistry to ‘see’ PAX8 protein inside cells. The PAX8 protein is normally found in a part of the cell called the nucleus.
Positive for PAX8 means that the PAX8 protein was seen inside the cells of interest in the tissue sample. Reactive is another term that pathologists use to describe cells that are producing PAX8.
Negative for PAX8 means that the PAX8 protein was not seen inside the cells of interest in the tissue sample. Non-reactive is another term that pathologists use to describe cells that are not producing PAX8.