The results showed that overexpression of USP5 increased the protein level and stability of METTL3 in 5-8F and CNE2 NPC cells (Figure S3A-B) and decreased the ubiquitination of METTL3 (Figure 3E), However, overexpression of USP5 dramatically decreased K48-linked ubiquitin chain but not the K63-linked of METTL3 (Figure 3F), suggesting that USP5 deubiquitinates K48-linked ubiquitin chain of METTL3. Here, METTL3 is linked to nasopharyngeal carcinoma.