May play an important role in the progression of epithelial malignancies. Binds 1 Ca(2+) ion per subunit. Binds 2 Zn(2+) ions per subunit. Specifically expressed in the mammary gland during apoptosis. The conserved cysteine present in the cysteine-switch motif binds the catalytic zinc ion, thus inhibiting the enzyme. The dissociation of the cysteine from the zinc ion upon the activation-peptide release activates the enzyme. The precursor is cleaved by a furin endopeptidase. Belongs to the peptidase M10A family.