IL9 and breast cancer: Also, regulation enzymatic functions (i.e., aromatase, estrogen metabolizing enzymes CYP 4A, CYP19 suppressing COX‐2 expression, or regulating GSTP1), targeting cell signaling (NF‐κB, PI3K/Akt, MAPK/ERK, p‐mTOR, Wnt, Notch‐1, hedgehog), epigenetics control (regulating DNA methylation and histone modification), activate immune system (NK cell, CD8+ T, CD4+ T, cytokines like IL‐9 and IL‐13) in BC cell lines.