As cancer promoters, on the one hand, MCs contribute to the stimulation of angiogenesis and lymphangiogenesis along with the degradation of ECM by producing different pro-angiogenic molecules (vascular endothelial growth factor (VEGF)-A, VEGF-B, FGF-2, heparin, histamine and stem cell factor (SCF)) [162–166], lymphangiogenic molecules (VEGF-C and VEGF-D) [167], matrix metalloproteinase-9 (MMP-9) and proteases (tryptase and chymase) [168, 169]. The gene discussed is MMP9; the disease is cancer.