Fig. 1

METTL3 expression is upregulated in CCA tissues. A Heatmap of m6A methylation-related differentially expressed mRNAs between CCA tissues and normal tissues. These differentially expressed mRNAs were identified by using TCGA-CHOL data. Red and blue indicate upregulated and downregulated mRNAs in CCA tissue compared with normal tissue, respectively. B METTL3 expression in the GEPIA2 dataset. The red box indicates CCA tumor tissue, and the gray box indicates normal tissue. C METTL3 expression in the TCGA-CHOL dataset. Tumor tissue, n = 36, normal tissue, n = 9. D Representative image of METTL3 expression in tumor and peritumoral tissue in the CCA tissue microarray. Compared with peritumoral tissues, METTL3 was overexpressed in CCA tissues, as revealed by IHC staining for METTL3 in a CCA tissue microarray (n = 60). Scale bar: 500 μm. E The METTL3 score in CCA tissues was significantly higher than that in peritumoral tissues. The sample sizes were 60 for the CCA tumor and peritumoral tissues. F Representative image of METTL3 expression at three levels in the CCA tissue microarray. METTL3 expression was scored at three levels (weak, moderate, and strong) on the basis of IHC staining intensity. Scale bar: 500 μm. G The overall survival analysis showed that high expression of METTL3 (red line) indicated a poor prognosis in patients with CCA. The median was used to define the cutoff, which was less than 3 for the low group. *Means P < 0.05, **means P < 0.01, ***means P < 0.001