XIST and esophageal squamous cell carcinoma: For females, most of expression of X-linked genes are regulated by XCI, which occurs during fetal period and determined by XIST and its antisense, TSIX. Thus, we measured the expression levels of XIST, TSIX and FMR1-AS1 in ESCC tissues to determine whether FMR1-AS1 had a correlation with XIST or TSIX. The results suggesting that the TSIX expression may also influence FMR1-AS1 in female ESCC (Fig. 2k, l).