Class III Beta-Tubulin Expression in Endometrial Tumors.
Michele Lomme, Nada Kawar, Don Dizon, Dwayne Lawrence. Women & Infants Hospital of Rhode Island, Providence, RI
Background: Tubulin, the major building block of microtubules, functions as structural and mobile elements in mitosis, intracellular transport, and in the cytoskeleton. Recent studies have shown that increased tumor expression of the class III beta-tubulin isotype (b3T), correlates with poor clinical outcomes in patients with various malignancies. These include breast, ovarian, gastric, and non-small cell lung cancers. Studies suggest that these poor clinical outcomes, in the setting of b3T overexpression, are related to resistance to tubulin-binding chemotherapeutic agents, such as taxanes and vinca alkaloids, used in the treatment of these malignancies. Treatment of endometrial cancer may also be treated with tubulin-binding agents. The purpose of this study is to investigate b3T expression in endometrial tumors.
Design: Endometrial cancer cases were identifed from the hospital database for a 3 year period. General information, including patient demographics, tumor characteristics, chemotherapeutic agents used, and survivor data, was collected using pathology reports, clinical records, and tumor registry data. Residual formalin fixed paraffin-embedded tissue, archived in the Department of Pathology, was retrieved for each tumor and subjected to immunohistochemical staining for b3T. Slides were evaluated for the presence of staining and scored semiquantitatively on a 4-tiered scale based on percentage of total tumor area staining and intensity of staining.
Results: Ninety-six uterine cancer cases were stained for b3T. The majority (n=64) were adenocarcinomas (45 endometrioid, 10 serous, 9 endometrioid with mucinous differentiation). Approximately half (46.8%) of adenocarcinomas showed b3T over expression. The majority of sarcomas (85.7%) were negative for b3T. Among carcinosarcomas, 64.3% showed b3T over expression, almost exclusively in the carcinomatous component. When comparing b3T positive to b3T negative tumors, no statistically significant differences were seen among demographic characteristics, stage or grade of tumors, or among chemotherapeutic modalities. However, tumors showing b3T over expression were more likely to have lymphovascular invasion (47.9% vs. 14.6%, p=0.001) and a worsened uterine cancer specific survival.
Conclusions: Differential class III beta-tubulin staining patterns are seen in endometrial cancers across all histologic subtypes. Further investigation is warranted to further characterize the correlation between class III beta-tubulin positivity and clinical outcomes.
Category: Gynecologic & Obstetrics
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 192, Wednesday Afternoon