For all CD3+ T lymphocytes and CD4+ T-helper (Th) lymphocytes, there were no significant associations between patients with high and low levels regarding clinicopathological variables such as age, tumor histological subtype, Nottingham histological grade, tumor size, hormone receptor status, number or localization of metastases or type of MBC (MBC at initial breast cancer diagnosis [de novo MBC] or distant recurrent MBC, Supplementary File S1). This evidence concerns the gene CD4 and breast cancer.