The mucin expression profile of endometrial carcinoma and correlation with clinical-pathologic parameters.

Mucin expression patterns have been studied in tumors from various sites. Previous studies have shown an association of MUC1 with poor prognosis and MUC2 and MUC5AC with a mucinous phenotype. The pattern of mucin expression in endometrial carcinomas has not been documented in a large series. We determined the mucin expression profile in endometrial carcinomas and evaluated the relationship between mucin expression and clinical-pathologic parameters. A tissue microarray of 310 cases of endometrial carcinoma with known clinical outcome was constructed from formalin-fixed, paraffin-embedded donor blocks using two 0.6 mm cores from each tumor. Sections were stained with monoclonal antibodies against MUC1, MUC2, MUC4, MUC5AC, and MUC6. Staining was considered positive if greater than or equal to 5% of cells stained positively in either core. Mucin expression was correlated with tumor type, histologic grade, International Federation Gynecology and Obstetrics stage, lymph node involvement, depth of myometrial invasion, patient age, ethnicity, and clinical outcome. MUC1 was expressed in 267/310 (86.1%) of endometrial carcinomas, MUC2 in 2/310 (0.6%), MUC4 in 73/310 (23.5%), MUC5AC in 1/310 (0.3%), and MUC6 in 4/310 (1.2%). Endometrioid endometrial carcinoma showed a higher rate of MUC1 expression than nonendometrioid endometrial carcinoma (227/258, 88.0% vs. 39/52, 75.0%, P=0.01). No significant differences in any of the mucins were noted among the other end points evaluated. Mucin expression did not correlate with tumor grade, stage, or patient outcome.