To determine whether 4T1 cell-derived GM-CSF contributes to the expression of Mcp-1, Ccl17 or Rankl mRNA by 4T1 tumors, we neutralized GM-CSF by intraperitoneal injection of anti-GM-CSF antibody and examined the expression of these genes by 4T1 tumors two weeks after the transplantation of tumor cells. This evidence concerns the gene CSF2 and neoplasm.