Tumor markers hold the promise of a revolution in disease diagnosis and therapeutic monitoring, provided that major challenges in genomics, proteomics and related disciplines can be addressed. The regulatory standards to be met by new measurement technologies for the clinical laboratory are very high. The measurements must not only be accurate, they must have a concrete medical implication. Squamous cell carcinomas (SCCs) show various clinical and histological features according to their epithelial differentiation stage. Generally, poorly differentiated SCCs are known to grow more rapidly and...