To exclude the possibility of a complete hydatidiform mole or androgenic mosaicism, we conducted immunohistochemical staining on p57KIP2, the protein product of the maternally expressed imprinted gene cyclin-dependent kinase inhibitor 1C (CDKN1C), which is not expressed in cells of pure androgenetic origin. Here, CDKN1C is linked to hydatidiform mole.