Figure 4J displayed that circ_0040039 was the most upregulated circRNA in IDD group through the analysis of GSE67566. Furthermore, Western blotting assay demonstrated that circ_0040039 inhibited the protein expression level of ESR1 (Figure 4K). Taken together, these data suggested that circ_0040039 might regulate the miR-874-3p-ESR1 pathway via a stabilization mechanism rather than a canonical ceRNA mechanism, as previously reported (Piwecka et al., 2017; Chen et al., 2019). The gene discussed is ESR1; the disease is intervertebral disk degenerative disorder.