PAX8 Differentiates Gastrointestinal Carcinomas from Mucinous Carcinomas of the Ovary, but Not Mucinous Carcinomas Arising in Ovarian Teratomas
Michael A DiMaio, Reetesh K Pai, Teri A Longacre. Stanford University, Stanford, CA
Background: PAX8, a transcription factor involved in organogenesis, is expressed in tumors of the thyroid gland, kidney, and Mullerian system. Recent data suggests PAX8 is useful in distinguishing mucinous tumors of the ovary from the GI tract, but this has not been confirmed; in addition, PAX8 expression in mucinous carcinomas arising from ovarian teratomas has not been studied. We examined PAX8 expression in a large series of primary GI carcinomas, primary ovarian mucinous tumors, and mucinous carcinomas arising from ovarian teratomas to determine the utility of PAX8 in distinguishing these lesions.
Design: Tissue microarrays (TMAs) containing 174 colorectal adenocarcinomas, 103 gastric adenocarcinomas, and 30 pancreatic ductal adenocarcinomas were stained for PAX8. TMAs and whole sections comprising 20 primary ovarian mucinous tumors (16 carcinomas, 4 borderline tumors) and whole sections of 10 mucinous carcinomas arising in ovarian teratomas were also stained for PAX8.
|Tumor type||PAX8 Reactivity (%)|
|Colorectal adenocarcinoma||2/174 (1.1%)|
|Gastric adenocarcinoma||2/103 (1.9%)|
|Pancreatic adenocarcinoma||1/30 (3.3%)|
|Primary ovarian mucinous tumors||13/20 (65%)|
|Mucinous carcinomas arising in ovarian teratomas||0/10 (0%)|