To better explore CXCL8 expression in tumor tissue samples, the UALCAN database was next utilized, revealing that relative to corresponding normal tissue controls, CXCL8 levels in tumors were elevated in colon adenocarcinoma (P < 0.01), rectum adenocarcinoma (P < 0.01), stomach adenocarcinoma (P < 0.01), thyroid carcinoma (P < 0.01), and head and neck squamous cell carcinoma (P < 0.01), whereas it was downregulated in bladder urothelial carcinoma as compared to tumor tissues (P < 0.01) (Fig. 4). This evidence concerns the gene CXCL8 and bladder transitional cell carcinoma.