CCND1 and testicular teratoma: Our results suggested that the expression of a cell cycle gene, Ccnd1, was upregulated by Dnd1 deficiency via the loss of Ezh2 expression and of H3K27me3 in Dnd1ter/ter testicular germ cells (Fig. 7F), and this molecular pathway may play a role in testicular teratoma development in Dnd1ter/ter testes.