PARP1 and neoplasm: PARP1 promotes the expression of HIF-1α by activating nuclear factor-κB (NF-κB) and promotes the polarization of macrophages M2, leading to the up-regulation of tumor-related macrophages (TAMs), such as tumor necrosis factor-α (TNFα) and IL-6, thus promoting the proliferation, invasion and metastasis of tumor cells, promoting the formation of tumor microvessels and microlymphatics37.