MMP9 and neoplasm: Lombardi et al. (2013) observed that IgG had an important role in the tumor vascularization fundamental in tumor growth and metastasis process in the MCF-7 tumor cell line; furthermore, IgG from patients in stage I contributed to the VEGF-A expression and production, and upregulation of matrix metalloproteinase-9 (MMP-9) by the activation of mAChRs (M3/M4); these effects were diminished by a muscarinic antagonist as atropine and increased by a cholinergic agonist as carbachol [57].