[6] Furthermore, and consistent with an important biological function, Maspin knockout mice were reported to be non-viable, dying in early embryogenesis.

[7] However, a subsequent study using viral transduction as a method of gene transfer (rather than single cell cloning) was not able to reproduce the original findings and found no role for maspin in tumour biology.

[5] The primary function of most members of this family is to regulate the breakdown of proteins by inhibiting the catalytic activity of proteinases.

Through this mechanism of action, serpins regulate a number of cellular processes including phagocytosis, coagulation, and fibrinolysis.

The catalytic serine residue in the protease target attacks the stressed conformation of the RSL loop to form an acyl intermediate.

[8] Importantly, and in contrast to original reports, maspin knockout mice are viable, displaying no overt phenotype in the absence of suitable biological or environmental challenge.