Elevated choline metabolism has been observed in various malignancies and is associated with poor prognosis.[52,53] An increased CD4/CD8 ratio typically reflects immune imbalance, particularly reduced activity of cytotoxic CD8+ T cells, which may weaken antitumor immunity.[54] Therefore, we hypothesize that this T cell subset may promote BC development and progression by influencing choline metabolism. Here, CD8A is linked to breast cancer.