PAX-8 (Paired box protein 8)

Source :
PAX-8 is expressed in the thyroid, non-ciliated mucosal cells of the fallopian tubes and simple ovarian inclusion cysts, but not normal ovarian surface epithelial cells. The antibody against PAX-8 is well suited for the detection of the protein in ovarian clear cell carcinoma. The cellular localization is nuclear. PAX-8 is expressed in the thyroid (and associated carcinomas), non-ciliated mucosal cells of the fallopian tubes and simple ovarian inclusion cysts, but not normal ovarian surface epithelial cells. PAX-8 is expressed in a high percentage of ovarian serous, endometroid, and clear cell carcinomas, but only rarely in primary ovarian mucinous adenocarcinomas. Studies have also found PAX-8 expression in renal tubules as well as renal carcinoma, nephroblastoma and seminoma. Over 98% of clear cell RCCs, 90% of papillary RCCs, and 95% of oncocytomas were positive for PAX-8, frequencies which are similar or better than for PAX-2. Normal lung and lung carcinomas do not express PAX-8. Similarly, the absence of expression of PAX-8 in breast and other non-GYN carcinomas other than those primary to the thyroid indicates that PAX-8 is an important new marker of ovarian cancer and a useful marker for the differential diagnoses in lung and neck tumors, or tumors at distant sites where primary lung carcinoma or thyroid carcinoma are possibilities. PAX-8, combined with organ system-specific markers such as uroplakin, mammaglobin, and TTF-1 can be a very useful panel to differentiate the primary site of invasive micro-papillary carcinomas of ovary from those of the bladder, lung, and breast. The ZR1 antibody does not react with pancreatic neuroendocrine tumors, thymic tumors, and lymphocytes. Synonyms: Paired box protein 8 <