Claudin-3 and Claudin-4 expression in serous papillary clear cell and endometrioid endometrial cancer

摘要

The tight junction (TJ) proteins claudin-3 and claudin-4 have been reported to be differentially expressed in uterine serous papillary carcinoma (USPC), a rare form of endometrial cancer characterized by a particularly high recurrence rate and poor prognosis. Preclinical experiments suggest that increased expression of both TJ proteins may in part mediate the biologically aggressive phenotype of USPC. Our aim was to determine claudin-3 and claudin-4 expression in a large cohort of surgically staged patients with USPC and clear cell endometrial cancer (n=137), and to compare the expression pattern and prognostic relevance of both claudins with that seen in patients with endometrioid endometrial cancer (n=150). The rate of claudin-3 and claudin-4 expression was significantly higher in USPC and clear cell endometrial cancer compared to endometrioid endometrial cancer (claudin-3: 78% and 61% versus 38%, p <.0001; claudin-4: 56% and 44% versus 9%, p <.0001). Furthermore, expression of both tight junction proteins was significantly associated with poor clinical outcome (claudin-3, DFS: Risk ratio (RR) 1.70, p=.0087, OS RR 1.62, p=.0247; claudin-4, DFS RR 2.66, p<0.0001, and OS RR 2.50, p<0.0001). However, claudin-3 and claudin-4 expression did not maintain prognostic independence in multivariate analyses, as their expression was tightly associated with more advanced disease stages (p <.0001 for both), and higher nuclear grade (p <.0001 for both). These clinical observations confirm the hypothesis based on preclinical evidence that increased expression of claudin-3 and claudin-4 may contribute to the aggressive phenotype of endometrial cancer of serous papillary or clear cell histology and suggest their potential utility as diagnostic biomarkers and possible targets for therapeutic intervention.