is a transcriptional repressor whose normal activity may establish a balance between survival and apoptosis of neural crest-derived cells required for proper craniofacial morphogenesis. The encoded protein may also have a role in promoting cell growth under certain conditions and may be an important target for the RAS signaling pathways. Mutations in this gene are associated with parietal foramina 1 and craniosynostosis type 2. In contrast, high expression of the MSX2 gene was detected in several cell lines derived from human tumors. In addition, they found that the full-length human MSX2 cDNA induced transformation in chicken myoblast cultures, supporting the view that MSX2 promotes rather than suppresses cell growth under certain conditions.