CXCL8 and esophageal squamous cell carcinoma: Our results revealed that after injecting normal humanized NK cells via the tail vein, the tumour size of BALB/c nude mice was significantly lower than that of mice injected with NK cells co-cultured with ESCC#1 supernatant; furthermore, the tumour size was restored by the addition of IL-6 and IL-8 antibodies (Fig. 5a and b).