Fig. 2

Antiestrogen regimens participate in reshaping tumor immune microenvironment. Blocking or downregulating ERα with SERMs/SERDs and estrogen deprivation can enhance PD-L1 expression and immunogenicity of BC, as well as regulate multiple factors secreted by BC cells, such as TGFβ, CCL-2 and CCL-5, indirectly modulating the tumor immune microenvironment. Enhanced NK cell-mediated antibody-dependent cytotoxicity (ADCC) increased the infiltration of CD4+ T cells, CD8+ T cells, and DCs and decreased the counts of Tregs and MDSCs within tumors can be found after anti-estrogen regimens treatment. Estrogen deprivation can lead to a greater inhibition of Tregs infiltration in tumor and block the production of CCL-2 by mast cells due to simultaneous suppression of ERβ signaling