When mast cells (MC), which play an essential role in inflammation conditions including asthma, are activated, several inflammatory compounds such as growth factors, cytokines, histamine, and a large number of different MC-restricted proteases, like carboxypeptidase A3 (CPA3), chymase, and tryptase, are released into the extracellular space [25–27]. The gene discussed is CPA3; the disease is asthma.