Maspin (mammary serine protease inhibitor) is a protein that in humans is encoded by the SERPINB5gene.[5] This protein belongs to the serpin (serine protease inhibitor) superfamily.[5]SERPINB5 was originally reported to function as a tumor suppressor gene in epithelial cells, suppressing the ability of cancer cells to invade and metastasize to other tissues.[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.[8] Furthermore, the latter study demonstrated that maspin knockout mice are viable and display no obvious phenotype.[8] These data are consistent with the observation that maspin is not expressed in early embryogenesis.[8] The precise molecular function of maspin is thus currently unknown.
^Zou Z, Anisowicz A, Hendrix MJ, Thor A, Neveu M, Sheng S, Rafidi K, Seftor E, Sager R (1994). "Maspin, a serpin with tumor-suppressing activity in human mammary epithelial cells". Science. 263 (5146): 526–9. Bibcode:1994Sci...263..526Z. doi:10.1126/science.8290962. PMID8290962.
^Gao F, Shi H, Daughty C, Cella N, Zhang M (2004). "Maspin plays an essential role in early embryonic development". Development. 131 (7): 1479–89. doi:10.1242/dev.01048. PMID14985257. S2CID10572194.
