Differential expression of the keratin-4, -13, -14, -17 and transglutaminase 3 genes during the development of oral squamous cell carcinoma from leukoplakia

To identify differentially expressed genes during the development of oral malignancy, differential display, northern blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical analyses were undertaken using oral squamous cell carcinoma (OSCC) and leukoplakia tissues. Significantly higher levels of keratin (Ker)-14 and -17 mRNAs, combined with lower levels of Ker-4, Ker-13 and transgtutaminase 3 (TG-3) transcripts, were observed in OSCC and severely dysplastic tissues, whereas this expression profile was reversed in hyperplasia and in mild to moderate dysplasia. The expression of Ker-4 and Ker-13 was elevated in density-arrested OSCC cell tines (Ca9-22, HSC-2, -3 and -4) but the expression of Ker-17 mRNA was elevated in these cells, regardless of the growth conditions. In addition, Ker-4 and Ker-13 proteins were predominantly expressed in moderate dysplasia and hyperplasia, whereas Ker-17 was markedly expressed in OSCC tissues. The expression patterns of these genes could therefore be an important determinant of the manifestation of oral malignancy. (c) 2005 Elsevier Ltd. All rights reserved.