TGF-α is an EGF-related polypeptide growth factor that signals through the EGF receptor, and stimulates the proliferation of a wide range of epidermal and epithelial cells. It is produced by monocytes, keratinocytes, and various tumor cells. TGF-α is a well-characterized mammalian growth factor that might contribute to the development of Cleft lip and palate (CL/P).