Cripto is a developmental oncoprotein and a member of the epidermal growth factor-Cripto, FRL-1, Cryptic family of extracellular signaling molecules. In addition to having essential functions during embryogenesis, Cripto is highly expressed in tumors and promotes tumorigenesis. During development, Cripto acts as an obligate coreceptor for transforming growth factor ␤ (TGF-␤) ligands, including nodals, growth and differentiation factor 1 (GDF1), and GDF3. As an oncogene, Cripto is thought to promote tumor growth via

The 83-mer sequences used to generate Cripto 1 and 2 short hairpin RNA vectors should read "5Ј-CTGTCTAGACAAAAACAATGACTCTGAATTAAAGTCTCTTGAACTTTAA TTCAGAGTCATTGCGGGGATCTGTGGTCTCATACA-3Ј" and "5Ј-CTGTCTAGACAAAAACTACAATGTCCTAACTGA ATCTCTTGAATTCAGTTAGGACATTGTAGCGGGGATCTGTGGTCTCATACA-3Ј," respectively.