Abstract
In the conventional view, CD4(+) regulatory T cell (T(reg)) represents a subset of lymphocytes that involve the perception and negative regulation of the immune response. CD4(+)T(reg) plays an important role in the maintenance of immune homeostasis and immune tolerance. However, recent studies have revealed that CD4(+)T(reg) do not suppress the immune response in some diseases, but promote inflammatory injury or inhibit tissue remodeling, suggesting the functional heterogeneity of CD4(+)T(reg). Their involvement in tumor pathogenesis is more complex than previously understood. This article reviews the relevant research on the heterogeneity of CD4(+)T(reg), subtype classification, and their relationship with tumor therapy.