TM4SF1 and cancer: Transmembrane 4 L six family 1 was detected at low or moderate levels in various normal human and mouse tissues, including the endothelium, skin, lung, and germ cells (Edwards et al., 1995; Tascou et al., 2001), In contrast, TM4SF1 has been shown to be highly expressed in the cytomembrane of numerous cancers (Table 1) and abundantly localized at the cell membrane surface and in late endocytic organelles (Lekishvili et al., 2008).