The contribution of the B7x immunological checkpoint to the growth of the Treg population within the tumor was discussed by John et al. In accordance with their suppressive function, B7x+ Tregs exhibited a higher level of TGF-LAP (a surface marker of TGF production) and a lower percentage of ki67 marker, indicating that they originated from peripherally converted CD4+ T cells. The gene discussed is VTCN1; the disease is neoplasm.