CDK1 and teratoma: Other drugs widely used in anticancer clinical practice, such as etoposide, which is an inhibitor of DNA topoisomerase II activity 28 or, more recently, purvalanol (dinaciclib for in vivo applications), which is a CDK1 inhibitor, could be alternatively used, or used in combination, to maximize residual pluripotent cell purge and further minimize in vivo posttransplant teratoma risk 29.