We have demonstrated that knockdown of XIST induces cell cycle arrest at G0/G1 phase by regulating cell cycle-related genes in PC cell lines; given that miR-140/miR-124 could directly bind to XIST and the 3’UTR of iASPP, we then investigated whether XIST regulates cell cycle-related genes through miR-140/miR-124/iASPP. This evidence concerns the gene XIST and pachyonychia congenita.