POU5F1 and teratocarcinoma: We noted similar changes in Cbx7 expression when 46C ESCs were induced to differentiate into embryoid bodies (EBs) in an independent ESC line (Oct4-GIP ESC), and during retinoic acid-induced differentiation of P19 murine teratocarcinoma cells (Figures 1G–1I and Figures S1C–S1E).