 This protease (with alias such as tryptase-Clara and mast cell tryptase) is expressed in normal club cells and mast cells, and in some cancers.It's especially high expression is observed in the human mast cell line HMC-1, and in the human erythroleukemia cell line HEL.Plasminogen (PLG), from which originates the mini-plasmin that can cleave the F-protein, is highly expressed in liver cancers.