SLC7A11 and oral cavity squamous cell carcinoma: MiR-557 was sponged by circular RNA eukaryotic translation initiation factor 6 (circEIF6) in pancreatic cancer cells, miR-876-5p was sponged by circRNA CDR1 antisense RNA (circCDR1as) in oral squamous cell carcinoma cells, and miR-1261 was sponged by the circular RNA circ0097009 in hepatocellular cancer cells, all of which were linked to the upregulation of SLC7A11 (Cui et al., 2021; Lyu et al., 2021; Zhang T. et al., 2021) (Table 3).