Thymosins are polypeptide hormones secreted by the animal or human thymus, among which thymosin α1 (Tα1) has the strongest biological activity; can stimulate the T cell maturation and expression of interleukin-2, the interleukin-2 receptor, and cell adhesion molecule differentiation cluster 2; and can inhibit hepatitis B virus replication in HepG2 tumor cells. The gene discussed is IL2; the disease is neoplasm.