Cripto-1: A common embryonic stem cell and cancer cellmarker

Human Cripto-1 has been implicated in embryogenesis and tumorigenesis. During early embryonic development, Cripto-1 functions as a coreceptor for transforming growth factor-β family members, including Nodal/growth differentiation factors 1 and 3, and is essential for mesoderm and endoderm formation and anterior/posterior and left-right axis establishment. In normal adult tissues Cripto-1 is expressed at very low levels, while its expression significantly increases in approximately 50-80% of different types of human carcinomas. Overexpression of Cripto-1 in mouse mammary epithelial cells leads to their transformation in vitro and enhances migration, invasion, branching morphogenesis and epithelial to mesenchymal transition. Transgenic mouse studies have shown that overexpression of Cripto-1 in the mammary gland results in mammary hyperplasias and papillary adenocarcinomas. Furthermore, Cripto-1 is expressed at high levels in different types of human tumors. In conclusion, while during embryogenesis Cripto-1 performs specific and regulatory functions related to cell and tissue patterning, inappropriate expression of Cripto-1 in adult tissues leads to cell transformation and tumor progression.