Detection of serum soluble fragments of cytokeratins 8 and 18 in patients with squamous epithelial carcinomas of the upper aerodigestive tract

Abstract

During the development of squamous cell carcinomas of the head and neck (SCCHN), cytokeratin (CK) 18 and 19, which are typical for simple epithelia, show an elevated expression in tumor tissues. CK 8 was found to be overexpressed in cell lines of SCCHN. Epithelial tumors like normal epithelia express characteristic "pairs" of CK. The smallest of these pairs comprises CK 8 and 18. Therefore, the aim of this study was to serologically detect fragments of CK 8 and 18 (cyfra 8/18) in SCCHN patients. Sera of 151 patients with SCCHN were tested for cyfra 8/18 (cyfra 8/18 ELISA medac, Hamburg) before treatment. Thirty sera of healthy volunteers and 43 sera of patients with benign diseases of the head and neck region served as control and reference group, respectively. Thirteen patients were followed-up clinically and serologically after surgery. The serum cyfra 8/18 concentrations of those 13 patients were compared to their clinical run. The cut-off value for cyfra 8/18 was determined with a 95% specificity of the reference group and was fixed at 1.1 ng/ml. The sensitivity was 7%. No correlation was found between cyfra 8/18 and clinical parameters like tumor stage, grading, and tumor location. Cyfra 8/18 concentrations could be correlated to the clinical run of 5 of 13 followed-up patients. Because of its low sensitivity, the serological detection of cyfra 8/18 must not be seen as a sufficient tumor marker for SCCHN. Its clinical applicability for regular post-surgical controls seems to be restricted and appears inferior to the clinical usefulness of cyfra 21-1.