S13-057 DICE: dual-integrase cassette exchange Stanford researchers have developed a system for precise genetic modification of human embryonic stem cells (ECSs) and induced pluripotent stem cells (iPSCs). Michele Calos Ruby Yanru Tsai Alfonso Farruggio Matt Gamboa Bosiljka Tasic Fangfang Zhu Simon Hippenmeyer Birgitt Schuele