CD4 and breast carcinoma: Memory B cells were known to promote anti-tumor immunity by acting as antigen-presenting cells, while Endothelial_ACKR1 cells were associated with better prognosis in some tumors; CD4+ T regulatory cells_FOXP3 mediated peripheral immune tolerance and suppressed cellular immunity, including anti-tumor responses, whereas LAM1_FABP5 cells, which played an immune-suppressive role, were linked to poorer survival rates in breast cancer [42, 43, 61, 62].