PPBP and neoplasm: Typically, macrophages infiltrated in tumors, named tumor-associated macrophages (TAM), shows M2-polarization characteristics and promote tumor malignant progression by secreting a variety of cytokines (e.g., TGFB1 [13] and HMGB1 [14]) and chemokines (e.g., CCL17 [15] and CXCL7 [16]).