“…Also, a structurally related gene has been characterized in amphioxus, the AmphiTOB gene (Holland et al, 1997). In vertebrates, the whole family is composed of at least six members that have been named differently in different species: Btg1, Btg2 (Tis21 in mouse and PC3 in rat), Btg3 (also named ANA for Abundant in Neuroepithelium Area), Btg4 (PC3B), Tob (Tob1), and Tob2 (Bradbury et al, 1991;Fletcher et al, 1991;Matsuda et al, 1996;Rouault et al, 1996;Guehenneux et al, 1997;Yoshida et al, 1998;Ikematsu et al, 1999). It has been proposed to name the family as APRO (AntiPROliferative) (Matsuda et al, 2001), but most studies and genetic databases continue using the BTG/Tob nomenclature, which will be adopted in this report.…”