Immediately after BCG treatment, macrophages massively infiltrate tumors and become polarized towards a pro-inflammatory phenotype (M1-like, Tnfa positive), accompanied by an induction of several inflammatory cytokines such as tnfa, il1b and il6. Depletion of macrophages with L-clodronate completely abrogated the BCG anti-tumor effects, demonstrating that clearance and apoptosis are dependent on macrophage activity. The gene discussed is IL1B; the disease is neoplasm.