After the 5FU-resistant CRC sub-lines were established, we determined the XIST expression level, and found that XIST was significantly up-regulated in HT29 5FU-R and HCT116 5FU-R cells compared with wild-type HT29 and HCT116 cells, respectively (Figure 4D). The gene discussed is XIST; the disease is colorectal carcinoma.