CD4 and neoplasm: Th2 is one of the special subtypes of CD4+ helper T cell (Th cell) that mainly secretes cytokines such as IL-4, IL-5, and IL-10, and excessive Th2 cells could affect the tumour-suppressive immune microenvironment, seriously reducing the anti-tumour effect, leading to the malignant growth of tumours (Chen et al., 2013; Fang et al., 2018).