The study performed by Anz and colleagues [30] found that although medullary breast cancer (MBC) was strongly infiltrated by FOXP3+ Tregs, it still significantly associated with good survival because the number of intratumoral CD8+ CTLs exceeded the number of FOXP3+ Tregs in most MBC cases, indicating the more important role CD8+ CTLs played in deciding the prognosis of breast cancer. The gene discussed is CD8A; the disease is breast carcinoma.