Rationale for folate receptor alpha targeted therapy in "high risk" endometrial carcinomas.

Advanced and recurrent endometrial cancers account for the majority of deaths from this disease with limited therapeutic options. High grade, and nonendometrioid histology, pathologically characterize the endometrial tumors associated with adverse outcome and are classified as "high risk". The identification of molecular prognostic factors that might be targeted for therapy among "high risk" endometrial cancers is an active area of investigation. We hypothesize that the FRalpha, highly expressed in endometrial cancer cells, is a potential target for this disease. Our objectives were to determine if FRalpha overexpression is associated with adverse prognostic factors and worse outcome. Three hundred and thirty-two endometrial cancer cores were arrayed onto a tissue microarray and stained using a FRalpha-specific monoclonal antibody. Staining was scored as absent or weak and moderate or strong. Forty-one percent of 310 evaluable cases stained moderate/strong. Moderate/strong FRalpha staining was significantly associated with other poor prognostic factors including: advanced stage, nonendometrioid histology and high grade. An association was observed between moderate/strong FRalpha staining and recurrence (p < 0.0014). These findings support further exploring a role for FRalpha targeted approaches for therapy and diagnostics in endometrial cancer.

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

OBJECTIVE: Tight junction (TJ) proteins claudin-3 and claudin-4 may be differentially expressed in uterine serous papillary carcinoma (USPC), a rare form of endometrial cancer characterized by a particularly poor prognosis. Our aim was to determine the expression pattern and prognostic relevance of claudin-3 and claudin-4 in a large cohort of endometrial cancer patients of diverse histological type and stage. METHODS: Claudin-3 and claudin-4 expression was studied in a cohort of 287 patients with endometrial cancer including 137 cases of USPC or clear-cell histology using immunohistochemistry. Patients were completely surgically staged. Outcome data is available on all 287 patients. RESULTS: 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 TJ proteins was significantly associated with poor clinical outcome (claudin-3, DFS 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, both markers 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). CONCLUSION: 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.