Thus, B7-H4 not only plays an important role in BC progression, but may also be a new target for future BC treatment.[49] High levels of tumor-infiltrating T cells (TILs) are correlated with better treatment response and improved prognosis in BC.[50] While B cells are generally associated with antitumor immunity, certain subsets, such as tumor-associated regulatory B cells (Bregs), infiltrate BC tissues at significantly higher levels than in adjacent noncancerous tissues and correlate with increased tumor malignancy. This evidence concerns the gene VTCN1 and breast cancer.