The role of the B7 family in autoimmune thyroid diseases and thyroid cancer

The B7 family exerts complex and diverse immunomodulatory effects on the occurrence and development of thyroid diseases. The abnormal expression and polymorphisms of B7 family molecules in autoimmune thyroid diseases result in the disruption of immune tolerance, activation of autoreactive T cells, and thyroid tissue damage. The dysfunction of the B7 family is also closely related to the progression of thyroid cancer (TC) through remodeling the tumor microenvironment and mediating immune evasion. Of note, targeting the B7 family has become a promising strategy for TC treatment. In addition, B7 family signaling linking to immune cell subsets, tertiary lymphoid structure formation, and therapeutic response are also discussed. With the emerging findings of B7 family members in thyroid diseases, understanding the comprehensive roles and mechanisms of B7 molecules would facilitate the clinical translation of B7-based immunotherapy.