Inflammatory granulocytes decrease subcutaneous growth of melanoma in mice

Growing melanomas invade the subcutaneous tissues. We have compared the size of tumors implanted in the subcutaneous cavities of C57BL/6 mice where inflammatory reactions were induced before the injection of 5 x 10(5) melanoma cells (B16F10 cell line). Granulocytic inflammation of the subcutaneous cavities resulted in a significant decrease in the growth of the implanted melanomas, whereas monocytic inflammation had no effect on tumor growth. We conclude that granulocytes, but not monocytes/macrophages, have anti-tumor action on melanoma that invade the subcutaneous tissues.