Some neutrophil populations, known as tumor-associated neutrophils (TANs), promote cancer cell growth, invasion, and angiogenesis by producing matrix metalloproteinase-9 (MMP9), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF) at primary and metastatic sites (Geh et al. 2022). This evidence concerns the gene MMP9 and cancer.