– The three butyrophilin BTN3A molecules, BTN3A1, BTN3A2, and BTN3A3, are members of the B7/butyrophilin-like group of Ig superfamily receptors, which modulate the function of T cells. BTN3A2 is overexpressed in gastric tumors, and deletion of BTN3A2 inhibited proliferation, migration, and invasion of gastric cancer cells. The butyrophilin 3 (BTN3) receptors are implicated in the T lymphocytes regulation and present a wide plasticity in mammals. A thorough phylogenetic analysis reveals a concerted evolution of BTN3 characterized by a strong and recurrent homogenization of the region encoding the signal peptide and the immunoglobulin variable (IgV) domain in Hominoids, where the sequences of BTN3A1 or BTN3A3 are replaced by BTN3A2 sequence.