Role of CD24 Protein in Predicting Metastatic Potential of Uterine Cervical Squamous Cell Carcinoma in Patients Treated With Radiotherapy

Purpose: The protein CD24 is a cell surface protein that appears to function as an adhesion molecule; its expression has been shown to correlate with prognosis in a variety of tumors. The aim of this study was to evaluate the immunoreactivity of uterine cervical squamous cell carcinoma to CD24 and determine whether CD24 is associated with clinical and pathologic parameters, including prognosis. Methods and Materials: The expression of CD24 protein was immunohistochemically studied in 73 cases of uterine cervical squamous cell carcinoma. All patients were treated with definitive radiotherapy alone or with concurrent chemoradiotherapy. Two pathologists independently analyzed the immunostaining; they did not have knowledge of the patient outcomes and evaluated any changes according to the percentage of tumor cells stained as follows: negative, <5% reactive; and positive, >5% reactive. Results: Positive staining was found in 43 cases (58.9%). The immunoreactivity did not correlate with age, International Federation of Gynecology and Obstetrics stage, lymph node metastasis, or tumor size. For patients who were CD24 negative, the total failure and distant metastasis rates were decreased about 20% compared with the rates for patients who were CD24 positive. On univariate analysis, the 5-year distant metastasis-free survival rate of CD24-negative patients was significantly greater than that of the CD24-positive patients (84.7% vs. 66.7%, respectively, p = 0.0497). The International Federation of Gynecology and Obstetrics stage and CD24 expression were significantly associated with distant metastasis-free survival on multivariate analysis. Conclusions: CD24 expression was a significant independent prognostic factor for distant metastasis-free survival in patients with uterine cervical squamous cell carcinoma. In the future, prospective determination of CD24 expression might aid clinical practice in the selection of the appropriate therapy for individual patients.