Potential early markers of carcinogenesis in the mucosa of the head and neck using exfoliative cytology.

Patients with head and neck squamous cell carcinoma (HNSCC) who are thought to be cured are at high risk of development of a secondary primary tumour in the mucosa of the upper aerodigestive tract and the lungs. This phenomenon is in agreement with the concept of 'field cancerization', which implies that the whole mucosa is potentially condemned to the development of neoplasia. The hypothesis advanced in this study was that early markers of carcinogenesis should therefore be present in all cells of the mucosa of patients with HNSCC. The expression of cytokeratin 16, cytokeratin 19, and histo-blood group antigen H (ABH), type 2 chain was analysed by means of immunocytochemistry on exfoliated cells taken from six sites of the upper aerodigestive tract of the 'healthy' mucosa of previously untreated HNSCC patients (n = 25) and controls (n = 10). Statistically significant differences were found in the mucosal expression of these markers between patients and controls. Since no overlap in ABH type 2 chain expression existed between patients and controls and the expression between sites in a given individual was highly correlated, this marker was considered the most promising of those tested. These data suggest that cytokeratin 16, cytokeratin 19, and ABH type 2 chain are markers of field cancerization in easily available exfoliated cells, which may be applied to monitor and/or predict the occurrence of second primary tumours.