HCC is a small globular protein (13.3kDa) that functions in the body as an inhibitor of cysteine proteasesfrom the papain and legumain families. The efforts to solve the structure of this protein led to one ofthe first observations of the domain-swapping phenomenon accompanyingthe formation of dimers of native HCC.−,  The structure of themonomeric form of HCC, depicted in Figure , was resolved only for its point mutants, that stabilize the monomeric form. Here, LGMN is linked to hepatocellular carcinoma.