Expression of p16INK4a in Endometrioid Cancer Rat Model

Introduction: Endometrioid cancer is a common gynecological malignancy in women. Endometrioid cancer model which resembles endometrioid cancer in human is needed to understand molecular carcinogenesis and the development of new therapies. Decreased expression of p16INK4a, a tumor suppressor gene, is found in endometrioid cancer and has prognostic value. The expression of this protein in animal models has been studied to evaluate its similarity with human endometrioid cancer. Methods: Fifteen paraffin blocks of rat consist of 5 normal uterine tissues, 5 atypical hyperplasia of uterine tissues, and 5 endometrioid cancer tissues were stained for immunohistochemistry. Expressions of p16INK4a were analyzed using IHC profiler Image-J software. Results: The expression score of p16INK4a increased significantly in the hyperplasia group compared with the normal group (p = 0.003) and significantly decreased in the endometrioid cancer group compared to the normal group (p = 0.01). Excessive expression of the tumor suppressor gene in the hyperplasia group is one of the cell's mechanisms to reduce the proliferation activity. Conclusion: Highest expression of p16INK4a was found in hyperplasia group and decreased to negative expression in endometrial cancer group. These patterns were similar to human endometrial cancer.