SERPINB5 has been identified as a type II tumor suppressor gene in normal mammary epithelial cells by subtractive hybridization, and is located on human chromosome 18q21.3-q23 along with other serpin genes, such as squamous cell carcinoma antigens 1 and 2, PAI-2 and headpin [3, 4]. The gene discussed is SERPINB5; the disease is neoplasm.