In this study, we identified that estrogen could reduce BCG-induced immunotherapeutic function against urothelial carcinoma by down-regulating the expression of IL-6, integrin-α5β1 and TNF-α, which are the key molecules to mediate BCG-induced monocyte/macrophage recruitment and kill BCa cells, and importantly, ICI 182,780 could potentiate the function of BCG via increasing these key molecules’ expressions in vitro and in vivo. This evidence concerns the gene IL6 and urothelial carcinoma.