Tredan et al evaluated 204 patients with breast cancer and suggested that the decrease in the CD4+ T lymphocyte count might be associated with poor overall survival.29 In another study evaluating metastatic breast cancer, Yang et al30 reported that CD4+ T lymphocytes constituted a negative independent risk factor and had both predictive and prognostic value for progression-free survival.30 Here, CD4 is linked to breast cancer.