According to genetic analysis, tumor-associated macrophages (TAMs) can produce various molecules, including VEGF, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-8 (IL-8), platelet-derived growth factor (PDGF), thymidine phosphorylase, and MMPs involved in tumor angiogenesis; TAMs promote direct tumor angiogenesis by releasing proangiogenic factors (such as VEGF-A) in hypoxic regions of tumors. This evidence concerns the gene IL1B and neoplasm.