Expression of human cytokeratin 14 in normal, premalignant and malignant oral tissue following isolation by plaque differential hybridisation.

Differences in gene transcription between RNA samples extracted from oral normal and squamous cell carcinoma (SCC) tissue were examined using the technique of cDNA library differential plaque screening. A differentially expressed transcript was selected on the basis of it being under-expressed in the cancer tissue and was identified, using DNA sequencing, as cytokeratin 14. The level of cytokeratin 14 transcription in RNA samples extracted from a range of oral SCC and normal tissue, as well as "white patch" lesions, was then investigated. Cytokeratin 14 appeared to be significantly under-expressed in oral cancer specimens studied compared to normal and white-patch tissue (P < 0.01). The trend for higher levels of cytokeratin 14 transcription in the dysplastic "white patch" samples compared to that observed for the malignant tissue (P < 0.05) suggests that the decrease in cytokeratin 14 transcription is a late event in the carcinogenic pathway.