Squamous cell carcinoma antigen, SCCA Protein (Active)

Squamous cell carcinoma antigen (SCCA) is a member of the ovalbumin family of serine proteinase inhibitors (serpins) . SCCA is detected in the superficial and intermediate layers of normal squamous epithelium, whereas the mRNA is detected in the basal and subbasal levels. A neutral form of the protein (SCCA1, or SERPINB3) is found in normal and some malignant squamous cells, whereas an acidic form (SCCA2, or SERPINB4) is detected exclusively in tumor cells and in the circulation of patients with squamous cell tumors.SCCA1 shares 92% amino acid identity with SCCA2. Thus, the appearance of the acidic fraction of SCCA is correlated with more aggressive tumors. Ray et al. (2005) proposed that IL-4- and IL-13-stimulated SCCA gene expression is mediated via STAT-1 and STAT-6 activation, and by suppressing the production, and most likely by interfering with the signaling of these cytokines, UG inhibits SCCA gene expression associated with airway inflammation in asthma.

1. Schneider, S. S., Schick, C., Fish, K. E., Miller, E., Pena, J. C., Treter, S. D., Hui, S. M., Silverman, G. A. A serine proteinase inhibitor locus at 18q21.3 contains a tandem duplication of the human squamous cell carcinoma antigen gene. Proc. Nat. Acad. Sci. 92: 3147-3151, 1995. 2. Ray, R., Choi, M., Zhang, Z., Silverman, G. A., Askew, D., Mukherjee, A. B. Uteroglobin suppresses SCCA gene expression associated with allergic asthma. J. Biol. Chem. 280: 9761-9764, 2005.