TBX1 and chordoma: Our in vitro and in vivo studies demonstrate that the VLP-based Cas9/gRNA RNP system allows for short-term (96 h) expression of Cas9 in chordoma cells while maintaining gene editing capacity and avoiding systemic toxicities, suggesting that our VLP-delivered Cas9/gRNA RNP-based gene editing therapy for brachyury-dependent chordoma is safe and effective.