Evaluation of serum fragments of cytokeratins 8 and 18 compared with squamous cell carcinoma antigen (SCC) in patients with stage I-III head and neck tumors

Serum fragments of cptokeratins 8 and 18 (CK 8/18) and squamous cell carcinoma antigen (SCC) were evaluated in 30 patients with stage I-III head and neck tumors, 35 patients with non-neoplastic lung diseases and 80 normal subjects (healthy blood donors). Serum concentrations of both markers were significantly higher in patients with cancer than in controls. For CK 8/18 the median values in normal subjects, non-neoplastic respiratory diseases and head and neck cancer were 0.64, 0.79 and 1.45 ng/mL, respectively. For SCC the results were 0.37, 0.75 and 0.96 ng/mL. No significant correlation was found between marker levels and tumor site and stage. At a specificity of 95% (determined in a group of subjects including healthy blood donors and patients with benign diseases) the sensitivity of CK 8/18 was 56.6% versus 47% for SCC. Despite the low sensitivity of single marker determination, combined measurement of CK 8/18 and SCC increases the sensitivity to 73% with a specificity of 90%.