Cytotoxic T lymphocyte associated antigen 4 expression predicts poor prognosis in luminal B HER2-negative breast cancer.

Cytotoxic T lymphocyte associated antigen 4 (CTLA-4) serves an important role in inhibiting anti-tumor immune response in the majority of solid tumors. However, a limited number of studies reported the function of CTLA-4 in luminal B HER2-negative breast cancer. Immunohistochemistry was performed to evaluate the expression of tumor and interstitial CTLA-4 in luminal B HER2-negative breast cancer tissues.