IL4 and breast cancer: Increasing evidence have demonstrated a crucial role of Th2 cells in orchestrating the progress and metastasis of tumors.353 In addition, Th2 cells and their cytokines were shown to construct an inflammatory TME involving M2-TAMs and promote tumor metastasis in breast cancer.354 For example, Th2 cells are known to produce IL-4, IL-5, and IL-13, and hence are able to regulate immunity.