CCL20 and neoplasm: In order to investigate whether macrophages are an important source of CCL20 in the tumor sites, double immunofluorescence staining was performed on cryo-sections derived from tumor biopsies of mice treated with MNU and H. pylori. We observed that in addition to F4/80+ macrophages, other cells also produced CCL20 in the tumor sites of mice (Figure 3C), indicating that CCL20 released by TAMs or others may induce Treg-cell migration to tumors.