While the induction of increased Xist RNA levels for 3 and 7 days in the presence of SPEN leads to statistically significant silencing of escapees in both NPC clones (that is, −Dox versus +Dox comparison), when this is done in the absence of SPEN (that is, −Dox versus +Dox, +Aux comparison), no significant changes in the allelic ratios of escapees were found (Fig. 3b,d–f and Supplementary Table 5). This evidence concerns the gene XIST and nasopharyngeal carcinoma.