The qRT-PCR results showed that circUBE4B was upregulated significantly expressed in the ESCC cells transfected with circUBE4B-Flag plasmids, circUBE4B-ATG-mut-Flag plasmids, and line-circUBE4B-173aa-Flag plasmids, while linear form of UBE4B mRNA expression was not obviously changed in the above groups of ESCC cells (Fig. 4B). The gene discussed is UBE4B; the disease is esophageal squamous cell carcinoma.