CASP9 and esophageal squamous cell carcinoma: In our quantitative analysis of apoptosis-related gene expression in ESCC cells, we found that there were relatively significant changes in four genes between the METTL3-knockout and NC groups, among which Bcl-2 and BIRC3 were down-regulated, while Bax and CASP9 were up-regulated in METTL3-knockout cells (Table S3 and Fig. S4A; Fig. 1J).