POU5F1 and testicular teratoma: In 129/SvJ Dnd1Ter/+ mice, acute foetal hypoxia (10% O2 for 12 h at E13.8–E14.3) increased bilateral testicular teratoma frequency from 3.3% to 64% and preserved OCT4/SOX2/NANOG expression as well as TGF-β family morphogen (Nodal) activity (Bustamante-Marin and Capel, 2023).