IL18 and neoplasm: On the one hand, IL-18 gene expression and serum levels are significantly higher in BC patients than in healthy individuals.34 IL-18 expression is low or negative in benign breast fibroadenomas but is elevated in tumor cells from most BC patients, with positive expression associated with lymph node metastasis.35 These findings suggest that high IL-18 expression in BC cells may promote the progression of BC.