POU5F1 and neoplasm: However, we have previously demonstrated that the multi-lineage outgrowths derived from t-hESCs have hallmarks of neoplastic teracarcinomas with higher self-renewal that teratomas and poor differentiation [13, 16] and we now find teratocarcinomas from t-hESC are less sensitive to radiotherapy and continued to contain cells that expressed Oct-4, suggesting the maintenance of multi-potent population within the tumour following radiation.