To further test whether the observed reluctance of a majority of NPC cells to activate Sox1 is a particularity due to the use of dCas9-VP64, we employed a composite CRISPR activator, VPR, additionally equipped with trans-activator domains of the NF-kappa-B p65 subunit and the R transactivator of Epstein–Barr virus (RTA)3,34. This evidence concerns the gene SOX1 and nasopharyngeal carcinoma.