Squamous cell carcinoma antigen, clinical application and analysis

The squamous-cel cancer antigen (SCC Ag) is expressed by squamous cells of skin, lung, digestive tract and uterine cervix. Its expression increases with increasing malignant transformation. Increased concentrations of SCC Ag can therefore be found in patients with squamous cell cancers. Although several publications describe the use of this tumormarker in squamous-cell cancers, like carcinoma of head- and neck, lung carcinoma, bladder carcinoma or rectal carcinoma, SCC Ag measurements are mainly used in follow up and/or prognosis of patients with cervix carcinoma. The SCC Ag belongs to the family of serine-protease inhibitors (Serpins) and is known to have two isoforms: SCCA1 and SCCA2. Current assays used for routine analysis of SCC Ag all detect both isoforms. Little is known about the sensitivity for both isoforms in current routine assays. In this paper we discuss assay characteristics and clinical application of the assays currently avalable for SCC Ag. Furthermore, preanalytical aspects and the results of a Dutch external quality-assurance initiative are discussed.