SERPINB5 and neoplasm: The maspin gene was originally identified in normal human breast epithelium as encoding a 42 kDa cytoplasmic protein, and is known to have tumour suppressive activity attributable to the inhibition of breast cancer cell motility, invasion, and metastasis (Sheng et al, 1994; Zou et al, 1994; Seftor et al, 1998).