Further, correlation analyses were performed revealing a significant positive correlation (p < 0.0019; R2 = 0.3438) between PLIN2 and COX-2 expression in EAC samples (Fig. 4C), whether no significant correlation was detected in ESCC samples (p = 0.1769; R2 = 0.07781) (Fig. 4D). This evidence concerns the gene PTGS2 and esophageal squamous cell carcinoma.