IgSF4 is thought to be derived from the ORF (open reading frame) existing in 11q23.2 of human chromosome No. 11. IgSF4 is known to be a suppressor gene of, mainly, a lung cancer. It is also reported that IgSF4 is involved in the junction of the brain nerves. Furthermore, it is reported that IgSF4 is expressed in the brain, testis and thyroid gland in normal cells.