Abstract:  Objective To explore the correlation between T cell subsets and expression of ER，PR，and Her-2 in breast cancer patients before and after postoperative radiotherapy， in order to develop markers to guide clinical prognosis and postoperative treatment of breast cancer. Methods Several T cell subsets（T，Th，Ts，NK）and the CD4⁺/CD8⁺ ratio in peripheral blood lymphocytes from 46 breast cancer patients were analyzed by standard four color flow cytometry on a BD FACS Calibur. Immunohistochemistry was used to assess expression levels of ER，PR，and Her-2 in breast cancer tissue. The correlation between T cell subsets and expression of ER， PR，and Her-2 in breast cancer patients was analyzed before and after postoperative radiotherapy. Results Expression of the ER receptor and PR receptor， which strongly correlated with Th cells（P=0.000 and 0.014， respectively），was significantly higher in the Th subsets that changed significantly as a result of radiotherapy than in the Th subsets that did not change significantly.No correlation was observed between T cell subsets and expression of ER，PR，or Her-2 before and after postoperative radiotherapy（P>0.05）. Conclusions Patients who are ER- or PR negative may show decreased immune function and poor prognosis after treatment with postoperative radiotherapy.

Key words:  Breast neoplasms, Radiation treatment, T cell subsets, ER, PR, Her-2