Interestingly, tryptase released from MCs is involved in tumour angiogenesis by several mechanisms: firstly, tryptase stimulates the formation of vascular tubes in in vitro and in vivo experimental models; secondly, tryptase is an agonist of the proteinase-activated receptor-2 in vascular endothelial cells that, in turn, induces angiogenesis [44]; thirdly, tryptase may stimulate the release of latent angiogenic factors bound to the extracellular matrix [45]–[47]. The gene discussed is F2RL1; the disease is neoplasm.