Expression of CD73 is associated with tumor progression and intratumoral inflammation in breast cancer.

CD73 is a lymphocyte differentiation antigen and highly expressed in many human solid tumors. CD73 is known to be associated with tumor progression, but its role in human breast cancer is still under investigation. The aims of this study were to evaluate the expression of CD73 in human breast cancer and to analyze its prognostic significance in breast cancer. A total of 198 patients who underwent surgery for the treatment of primary breast cancer were enrolled. Tissue microarrays (TMA) were constructed with breast cancer tissues and immunohistochemical staining for CD73 was performed on TMA tissue sections. The clinicopathologic characteristics were evaluated from the patient's medical records and pathologic reports. The average age of the patients was 51.7 ± 10.7. Positive expression rate of CD73 for all breast cancer was 25.4%. Positive rate of CD73 expression in invasive breast cancer was 30.9%, which was significantly higher than that of 5.4% of ductal carcinoma in situ. CD73 expression was significantly associated with higher T-stage, node metastasis, positive progesterone receptor status and presence of intratumoral inflammation. There was no significant association between molecular subtypes and CD73 expression. The disease-free survival (DFS) and overall survival (OS) rate at 5 years were 90.1% and 96.6%, respectively. There was no difference in DFS and OS according to CD73 expression. In conclusion, this study showed that CD73 expression is associated with tumor progression and inflammation in breast cancer. Our results suggest that CD73 has a potential as a prognostic marker and a therapeutic target of breast cancer.