The results showed that miR-224-3p was negatively correlated with NORAD and MTDH (Pearson R = − 0.389 and − 0.706, both P < 0.001) and that NORAD was positively correlated with MTDH (Pearson R = 0.541, P < 0.001) in ESCC specimens (Fig. 4j). The gene discussed is MTDH; the disease is esophageal squamous cell carcinoma.