Taken together, this is the first report of the vertebrate ROME gene producing a biologically active plasma membrane glycoprotein that is critical for normal development and metastasis.<h4>Significance</h4>This is the first report of a detailed characterization of the molecular features of ROME (INAFM2) protein in mammalian cells and its biochemical and biological functions related to vertebrate development and cancer metastasis. This evidence concerns the gene INAFM2 and cancer.