To elucidate the possibility that MUC2 regulates IL-6 secretion and induces a local immune response in colon cancer cells, we analyzed Ly6G+CD11b+ neutrophil, Ly6G−CD11b+ macrophage, CD4 T cell and CD8 T cell levels in the peritoneal fluid of mice with MUC2 RNAi-1 cell tumors treated with control or IL-6 neutralization antibodies. The gene discussed is CD4; the disease is malignant colon neoplasm.