[6][7] Cathepsin B is upregulated in certain cancers, in pre-malignant lesions, and in various other pathological conditions.

[14][15] Procathepsin B of 43/46 kDa is then transported to the Golgi apparatus, where cathepsin B is formed.

Cathepsin B may enhance the activity of other proteases, including matrix metalloproteinase, urokinase (serine protease urokinase plasminogen activator), and cathepsin D,[16][17] and thus it has an essential position for the proteolysis of extracellular matrix components, intercellular communication disruption, and reduced protease inhibitor expression.

[18] Cathepsin B has been proposed as a potentially effective biomarker for a variety of cancers.

[20] Cathepsin B has been shown to be involved in the pathogenesis of pancreatitis, by prematurely activating the digestive enzyme trypsinogen within the pancreas, leading to autodigestion of acinar cells.