This gene, which is a member of the tetraspanin superfamily, is one of several tumor-suppressing subtransferable fragments located in the imprinted gene domain of chromosome 11p15.5, an important tumor-suppressor gene region. Alterations in this region have been associated with Beckwith-Wiedemann syndrome, Wilms tumor, rhabdomyosarcoma, adrenocortical carcinoma, and lung, ovarian and breast cancers. This gene is located among several imprinted genes; however, this gene, as well as the tumor-suppressing subchromosomal transferable fragment 4, escapes imprinting. This gene may play a role in malignancies and diseases that involve this region, and it is also involved in hematopoietic cell function. Alternatively spliced transcript variants have been described, but their biological validity has not been determined.