Anti Squamous Cell Carcinoma Antigen 2 (SERPINB3A/SQN-5) pAb (Rabbit, Antiserum)

Squamous cell carcinoma antigen (SCCA) is a member of the ovalbumin family of serine proteinase inhibitors. The protein was isolated from a metastatic cervical squamous cell carcinoma by Kato and Torigoe (1977). SCCA is detected in the superficial and intermediate layers of normal squamous epithelium, whereas the mRNA is detected in the basal and sub-basal levels. The clinical import of SCCA has been as a circulating tumor marker for squamous cell carcinoma, especially those of the cervix, head and neck, lung, and esophagus. Many clinical studies of cervical squamous cell carcinoma show that the percentage of patients with elevated circulating levels of SCCA increases from approximately 12% at stage 0 to more than 90% at stage IV. Levels fall after tumor resection and rise in approximately 90% of the patients with recurrent disease. Similar trends occur in the other types of squamous cell carcinoma, with a maximum sensitivity of approximately 60% for lung, 50% for esophageal, and 55% for head and neck tumors. The neutral form of SCCA (SCCA1, or SERPINB3) is detected in the cytoplasm of normal and some malignant squamous cells, whereas the acidic form (SCCA2, or SERPINB4) is expressed primarily in malignant cells and is the major form found in the plasma of cancer patients. Thus, the appearance of the acidic fraction of SCCA is correlated with more aggressive tumors (summary by Schneider et al., 1995). Ray et al. (2005) stated that mouse Serpinb3a, or Scca2, exhibits the cysteine-like serine protease inhibitory function of human SCCA1 and the trypsin-like serine protease inhibitory function of human SCCA2. Thus, Scca2 is the mouse ortholog of both human SCCA1 and SCCA2. Ray et al. (2005) found that challenge of uteroglobin (UGB, or SCGB1A1)-knockout mice with chicken ovalbumin (OVA) resulted in elevated lung expression of Scca2, as well as elevated levels of the cytokines Il4 and Il13 in lung and exacerbated airway inflammation. These effects were countered by reintroduction of recombinant Ugb. Treatment of cultured human bronchial epithelial cells with IL4 or IL13 stimulated SCCA1 and SCCA2 expression via phosphorylation of the transcription factors STAT1 and STAT6. SCCA1 and SCCA2 expression was not upregulated by IL4 or IL13 in the presence of an inhibitor of tyrosine phosphorylation. Ray et al. (2005) proposed that UGB controls allergic asthma by downregulating signaling through IL4 and IL13 and inhibiting SCCA1 and SCCA2 expression. Anti-Serpinb3a antibody is a rabbit polyclonal antibody obtained from immunization with purified E. coli-derived recombinant mouse Serpinb3a. This antibody can be used for the detection of Serpinb3a by immunoblotting and immunostaining.

References:
Sakata, Y et al., Biochem. Biophys. Res. Commun. 324:1340-1345, 2004.