[Stefin A--potential application in oncological laboratory diagnosis].

This is a review of studies on stefin A, an intracellular cysteine peptidase inhibitor of cystatin superfamily. Cystatins and target cysteine peptidases, such as cathepsins B and L have been implicated in malignant progression. The biochemical characteristics of human stefin A and its functions are presented. Special attention was paid to the potential usefulness of stefin A determination in serum and tissue cytosol (ELISA test) or tissue sections (immunohistochemistry) in the oncological laboratory diagnosis.