Immunohistochemical Expression of Cyclin D1 in Renal Cell Carcinoma Subtypes

Background: Renal cell carcinoma (RCC) is the second-leading cause of mortality among urological malignancies and accounts for 2–3% of adult malignancies. Approximately 25% of patients experienced recurrence or metastasis subsequent to surgery, accompanied by radiation and chemotherapy failure. Cyclin D1, a critical regulator of the Growth/Synthesis (G1/S) transition, is a subject of significant research. Objectives: To assess the frequency of immunohistochemical expression of cyclin D1 in RCC subtypes and its association with some clinicopathological parameters such as age, gender, size of tumor, histological type, and grade. Methods: During a period of eleven months extending from March 2023 through January 2024, 64 RCC cases were included in this retrospective case series study, obtained from the histopathological departments of private laboratories in Mosul city, Iraq. An immunohistochemistry investigation using Cyclin D1 was performed, and data of the positive cyclin D1 expression were evaluated. Results: The mean age was 54.8 years, with male predominance (53%). Renal cell carcinoma cases included in this study show immunohistochemical expression of Cyclin D1, but with different staining grades. 39% were low expressers, versus 61% were high expressers. Cyclin D1 expression showed a significant association with age, histological type, tumor size, and nuclear grade, respectively. Conclusions: Cyclin D1 is overexpressed in renal cell carcinoma, and targeting it may benefit treatment and prevention. In renal cell cancer, cyclin D1 expression is associated with a favorable prognosis and can aid in predicting patient outcomes.